(First time) Building up RO water for an APA

[FatsSchindee]

Hey all,

My next batch will be my first all-grain brew (a Simcoe hop-bursted APA, BIAB), and have been reading up about water chemistry. I have always used RO from the store (at $0.27/gal from the machine) for my extract and PM beers, and want to continue using it for all-grain. I just figure it would be easier to build up from scratch than to figure out the composition of, filter and/or Campden, and then adjust, my tap water. I don't brew more than once a month, and smaller batches, so the cost is negligible to me. I read the primer sticky, and do like the idea of just keeping it simple (Gypsum and CaCl). I'm thinking even simpler, though, as it looks like I may not need any acidulated malt(?). I'm using brewersfriend for the recipe calc, and the associated water calc for the adjustments. It's showing that if I add 5 g gypsum and 3.5 g CaCl (and no acid malt), my mash pH will be 5.25 - right about where I'd want it, no?

Here are the specifics, so you can analyze something I may be missing (and to add to that, I haven't yet used a spreadsheet like Bru'n or Palmer's to double check the numbers, as I'm traveling with only my iPad at the moment, and don't have a spreadsheet app - so maybe those will calculate a different mash pH?):

3 gal batch (post-boil; to end up with at least 2.5 after kettle and ferm trub loss)... So 4.37 gal total (3 mash and 1.37 sparge - BIAB) water to be treated. 6 lbs of grain makes for a 2.0 qt/lb mash thickness. Grains are:
4.75 lbs pale ale malt 3.5L
10 oz light Munich malt 10L
6 oz Crystal40 40L
4 oz Victory 28L

Total IBU of ~44 from 3 oz Simcoe staggered (hop-bursted) from 15 min to flameout

Starting with RO water and adding 5 g gypsum (1.2 tsp) and 3.5 g CaCl (0.8 tsp) gives the following numbers:
Ca - 128
Mg - 0
Na - 0
Cl - 102.1
SO4 - 168.6
SO4/Cl ratio - 1.7
Alkalinity (as CaCO3) - 2.6
RA (as CaCO3) - -88.7
Effective water RA - -132.63
Grist DI water pH - 5.57
Mash pH - 5.25

Do those numbers look good for an APA? I varied from the 1 tsp/5 gal rec from the sticky just a bit by adding more gypsum (the 0.8 tsp would be about right for 4 gal water), as I want (I think... Based on some things I've read; though I've read differing opinions on everything, it seems, which makes this all somewhat confusing) the hops to stand out, and have read a higher SO4/Cl ratio does that (also since I'm not doing a standard early bittering charge, I want to make sure and accentuate the bitterness I do get from the late hops). I've also read that Ca shouldn't be much above 150, and that negligible Mg and Na are okay (get some from grain).

Because I want to keep it simple, I'm not springing for a pH meter yet. I ordered some 4-7 colorpHast strips, and will use those to monitor mash pH (I did read about them reading ~0.3 low, and will try to account for that). If my first few attempts at water modification end up screwing up the taste of my beer, then I'll feel justified buying the meter later. I think I'll buy some Phosphoric acid (seems to be better than Lactic because less flavor?) to have on hand, just in case the pH does measure too high in the mash (after 15-20 min to equalize, I understand). So that'll be my back up instead of the acid malt.

I've been reading up on the subject for the last few weeks (mainly on here, and some other blogs/sites online), and sometimes I feel like I have a decent grasp of the basics... But then I'll revisit part of it another day and realize I didn't understand it quite like I thought I did. Definitely a lot to digest! I've seen it said many times that water chemistry can be as easier or as hard as you make it... So I'm trying to make it as easy as possible for me for this first time! I appreciate any feedback and help I can get... Cheers!

 

[Glynn]

I have been using tasty Mcdoles profile for apa, ipa and doubles. He's numerous awards and use this profile on pretty much everything he makes. Using this profile i usually have to add anywhere from 2 to 4 oz acid malt

ca - 110
mg -18
na - 17
cl - 50
so4- 300 to 350
hco - 0

 

[grathan]

Do you notice any difference from changing water profiles? I've never really could tell if I added a little bit of this and that. Perhaps the magnesium, but that is it.

 

[ajdelange]

I may not need any acidulated malt(?). I'm using brewersfriend for the recipe calc, and the associated water calc for the adjustments. It's showing that if I add 5 g gypsum and 3.5 g CaCl (and no acid malt), my mash pH will be 5.25 - right about where I'd want it, no?

That's true. You may not. But then again, you may. With your recipe the two dominant factors that will set mash pH are the distilled water pH of the base malt and the calcium level. Assuming that the base malt is the one I modeled in detail (Weyermann's Pils which I assume it isn't) with its DI water pH of 5.62 and that the Kohlbach's observation that 3.5 Eq of calcium release 1 Eq of protons and that the other malts have DI pH's and buffering capacities predictable from Kai Troester's measurements the predicted pH would be 5.35. This Weyermann's base malt would need a total of 26.6 mEq of protons to shift to pH 5.35 and, again assuming Kolbach's model to be correct, calcium ion reaction would supply 20.75 of these with the colored malts supplying the rest. OTOH if the base malt has a DI pH 0.1 higher (5.72 - not atypical) the pH would be 5.44. IOW base malt DI pH has a tremendous influence here. There are a lot of ifs here. This is not an advertisement for pH meters but I think it is pretty clear why they are so valuable.

I haven't yet used a spreadsheet like Bru'n or Palmer's to double check the numbers, as I'm traveling with only my iPad at the moment, and don't have a spreadsheet app - so maybe those will calculate a different mash pH?)

Yes, they will. They use different models. Different from what I use and different from each other.

3 gal batch (post-boil; to end up with at least 2.5 after kettle and ferm trub loss)... So 4.37 gal total (3 mash and 1.37 sparge - BIAB)

I assumed all the calcium salts went into the mash water. If they are distributed over the 4.37 gal volume then the predicted pH rises to 5.40 (all the other assumptions the same).

Because I want to keep it simple, I'm not springing for a pH meter yet.

Seems use of a pH meter is a lot simpler than all these calculations/assumptions but that's just my opinion. After a few test mashes and brews using a pH meter you will develop the experience that lets you predict pH pretty closely without any calculations.

I ordered some 4-7 colorpHast strips, and will use those to monitor mash pH (I did read about them reading ~0.3 low, and will try to account for that).

Most do read 0.3 low but someone just posted about some he was using that read high. I don't really know, at this point, if pH strips are worse than no measurement but I'm coming around to that POV.

I'll feel justified buying the meter later.

It is a tool that an advanced brewer needs. When I polled (not a formal poll by any means just 'raise your hand if you use one') professional brewers at a regional MBAA meeting last weekend I was surprised to find that most do use them. Both of the breweries we visited (Flying Dog which is pretty big and Monocacy which is pretty small) had them.

I think I'll buy some Phosphoric acid (seems to be better than Lactic because less flavor?) to have on hand, just in case the pH does measure too high in the mash (after 15-20 min to equalize, I understand). So that'll be my back up instead of the acid malt.

I wouldn't worry about it. Based on the numbers I threw around you would be OK even if your base malt pH went as high as 5.8. I do think that's a lot of calcium and if you have that much it is going to impact mash pH.

I've been reading up on the subject for the last few weeks (mainly on here, and some other blogs/sites online), and sometimes I feel like I have a decent grasp of the basics...

Based on your comments and questions I'd say you do but this is an art and a science and there is still lots to learn - even for those of use that have been fiddling with it for 20 yrs or more.

 

[mabrungard]

Depending on how you are estimating that mash pH, 5.25 is not where you want to be. That is too low for the hops and bittering to come out. A low mash and wort pH will close down your hop expression and that is hardly what you want in an APA.

The proposed calcium and sulfate levels proposed by the OP are OK. However the chloride level is probably double what it should be. Please forget the tired guidance of the sulfate/chloride ratio. That ratio is only applicable in a narrow range of chloride content and some brewers think that it can be applied under any condition. Do take some of the advice that Tasty provided in his water profile for hoppy beers, excepting that the bicarbonate level of zero is too low. That will drive the mash and wort pH too low and that will end up reducing the hop expression as noted above.

For Glynn, I strongly recommend that you reduce or delete the acid malt addition so that the resulting pH is slightly higher. Be aware that driving the RA of the mashing water down with large doses of calcium and magnesium can require that the water have a bit of alkalinity to moderate the RA drop. That is the problem with McDole's water profile. The rest of it is OK.

If the OP is starting with low alkalinity water like RO, then there is no need to worry about the taste effect of lactic acid. The amount of acid that would need to be added to that low alkalinity water is far less than you could taste. There is no need to move to phosphoric acid for that reason. However, either acid is a fine choice.

Magnesium is definitely an asset in a hoppy and bittered beer. Sure, malt adds magnesium to the wort. But that Mg is bound up and doesn't change the taste. Added Mg can help boost the bitterness perceptions in the finished beer. Do be aware that the allowable Mg content in water of 40 ppm is a very real limit. Exceeding that content can degrade beer flavor by inserting an astringency that is unwelcome. The general recommendation that Mg should not be added to brewing water is generally sound if the brewer does not know how much Mg is in the tap water. When you do know that starting level, then you can add the teeny bit of Mg. By the way, I'm a little gun-shy of Mg, so I typically only take it about half way to that upper limit.

Regarding the upper limit for Ca of 150 ppm, there doesn't really seem to be a consequence of the high Ca excepting that there are some anions associated with that high Ca content and they are probably a reason that you would not want to take the Ca content that high.

Enjoy!

 

[FatsSchindee]

Thanks for the responses, all.

Glynn, thanks for the profile. It is good to see some other hard numbers (not just the theoretical underpinnings regarding the minerals, malts, and acids) that have made great beer for the style - I'm familiar with McDole's recipes from his work on the CYBI and Brewing with Style podcasts with Jamil. And I understand Martin's point made about that profile as well, which is part of the reason I felt I didn't need any acid malt.

AJ, point well taken about the pH meter and use by pro brewers. I've been brewing less than a year, so am definitely nowhere close, but understand that a meter would be a step in the right direction. Just don't want to make the extra purchase as of yet...
I buy my ingredients from AHS, as I live in Austin and don't have to worry about shipping. The Pale Ale malt in my recipe doesn't list a maltster on their website, just a Lovibond of 3.5. I plan on getting the ingredients in the next couple days, so I'll ask when I'm in there, if it makes a difference.
Also, I do plan on adding all the salts into the 3 gal mash, and just using RO for the sparge (I usually do a 10 min dunk sparge with BIAB to rinse the grains, but with only 1.37 gal for the sparge and 6 lbs grain I think the grain-in-colander and pour-over method may work better?). I do have the "add salts to mash only" box checked on the brewersfriend calculator, so I assume it is working the numbers that way. Would it be better to distribute them throughout the total, though, to drive the mash pH higher (re: Martin's response - see next paragraph)? If I uncheck the box, this does indeed happen (as your calculations and insight obviously show).

Martin, what would be a better pH for an APA? I only went by the general 5.1-5.5 rule of thumb I've seen many times, but didnt know about the differences between styles within that range. Would the higher end of 5.4-5.5 be better? The SRM is right around 9.5-10, if that matters (sounds like it doesn't much anymore, based on what I've been reading). Point taken about Mg and bitterness, also, as well as the Cl being too high for style (see below)...
Looking again at McDole's numbers, and plugging quantities into the calc, I see that any attempt at adding enough gypsum and Epsom to get the higher SO4 numbers does drive down the pH (due to the extra Ca and Mg, right?). So would adding some baking soda help (adds Na as well as alkalinity)? It appears to, when a gram or so is added to my numbers.

Based on these responses, I'll mess around with the additions some more, and see what I can come up with to better fit all your recommendations... Thanks!

Oh, and Grathan - I don't know; this is my first attempt at changing the profile (as it is my first attempt at all grain, and I've always just used 100% RO in my extract and PM batches thus far). The assumption is that yes, it does indeed make a difference (otherwise why would everyone be doing it, right? And I just mean with the RO - obviously many have good enough tap water that no additions are necessary. I just want to start from RO and build up...).

 

[ajdelange]

I failed to notice that this is your first attempt at all grain. Given that it is you are, in considering all these factors, trying to play the Goldberg Variations before tacking the Two Part Inventions IMO. Had I spotted this I would not have loaded you up with all that advanced arcana. My advice to you would be to treat all the water at once using 1/2 tsp of CaCl2 and 1/2 tsp of gypsum. Right now you need to be learning the fundamentals of all grain brewing and not the details of water management. This simple recommendation will give you a good beer. Assuming that you pull off the brew you can use it to learn what additional minerals would do to it. Taste some of it as is, some with added gypsum, some with added calcium chloride and some with both to see what the effects of these salts are. If you find they grant improvement use more in a second brewing of this same grain/hops bill.

As this simpler recommendation lowers calcium and the specialty malts have so little influence because they are used in modest quantity I would suggest some sauermalz - perhaps 1%.

In a nutshell keep it simple starting out. See the Primer at https://www.homebrewtalk.com/f128/brewing-water-chemistry-primer-198460/ for more on this KISS approach.

 

[Glynn]

For Glynn, I strongly recommend that you reduce or delete the acid malt addition so that the resulting pH is slightly higher. Be aware that driving the RA of the mashing water down with large doses of calcium and magnesium can require that the water have a bit of alkalinity to moderate the RA drop. That is the problem with McDole's water profile. The rest of it is OK.

Thank you mabrungard i will do that. If you get board this is my next brew. http://www.brewersfriend.com/mash-chemistry-and-brewing-water-calculator/?id=X13TL6V If you have any sugestion im open to hearing it.

To the OP keep in mind i know next to squat when it comes to addition. I chose tastys because it seemed like a good place to start. I have been AG brewing close to 2 yrs now but have only used RO + addition in my last 4 batches, 1 of which just became ready to drink. I am in no way an authority of what is a good profile

 

[FatsSchindee]

I failed to notice that this is your first attempt at all grain. Given that it is you are, in considering all these factors, trying to play the Goldberg Variations before tacking the Two Part Inventions IMO. Had I spotted this I would not have loaded you up with all that advanced arcana. My advice to you would be to treat all the water at once using 1/2 tsp of CaCl2 and 1/2 tsp of gypsum. Right now you need to be learning the fundamentals of all grain brewing and not the details of water management. This simple recommendation will give you a good beer. Assuming that you pull off the brew you can use it to learn what additional minerals would do to it. Taste some of it as is, some with added gypsum, some with added calcium chloride and some with both to see what the effects of these salts are. If you find they grant improvement use more in a second brewing of this same grain/hops bill. As this simpler recommendation lowers calcium and the specialty malts have so little influence because they are used in modest quantity I would suggest some sauermalz - perhaps 1%. In a nutshell keep it simple starting out. See the Primer at https://www.homebrewtalk.com/f128/brewing-water-chemistry-primer-198460/ for more on this KISS approach.

Yeah, as much as I can appreciate Bach's work, I'm no prodigy!
I did mention in the OP that I read the primer, and that is indeed what inspired me to KISS. Before that, I was looking at adding Epsom and table salts as well as the gypsum and CaCl, to try and hit numbers that others had posted... Without really fully understanding what I'd end up with or any background taste reference. So I think I'll take your advice to heart and just go with the 1/2 tsp (2 g) of gypsum and CaCl, along with the 1% acid malt (basically 1 oz for 6 lbs grain bill)... Or maybe bump the gypsum up to 3/4 tsp (3 g) since it's a hoppy Pale Ale.

Here's what each would give me:

2 g each, 1 oz acid malt:
Ca - 61.1
Cl - 58.3
SO4 - 67.5
Mash pH - 5.33
RA - -61.9

3 g Gypsum, 2 g CaCl, 0.5 oz acid malt (to reduce the lowering of pH since more Ca):
Ca - 75.2
Cl - 58.3
SO4 - 101.2
Mash pH - 5.34
RA - -61.5

I'm leaning toward the latter, with slightly higher Ca and SO4... Think it'll make much difference? I think what I'm taking away from the above posts is just to try something simple for the first attempt, and then taste and adjust from there (I like the idea of even adding the salts to the finished beer to test effects) for subsequent batches.

I was thinking I was maybe "biting off a bit more than I can chew" by trying all these new things at once (first all-grain, first bigger (not just PM) BIAB, first water adjustments, first APA recipe of my own devising, first time using Simcoe, first attempt at hop-bursting)... But if I tried changing only one thing at a time, it would take me the better part of a year to get to where I want to be (I only brew about once a month). So I figure I'll just brew it up this way, to the best of my ability, and see how it turns out. Then, if it's not good (I know it can always be better), I can analyze why, and "reverse engineer" from there. Worse case, it'll take me just as long, changing one thing at a time back to how I did it before. But many of the changes I need to do at once, with the equipment I have (and any new equipment would just be another change anyway). For example, to do all-grain on my equipment, I need to do BIAB, and since it's all-grain, I need to do the water adjustments as well, since I'm not using any extract as I usually do with the RO water. So I just figure at this point, "go big or go home"! My yeast starter is happily spinning away right now, and I hope to be brewing tomorrow or Thursday night. So we'll see how it goes...

Thanks for the advice.

 

[Glynn]

Ca - 75.2
Cl - 58.3
SO4 - 101.2

I tried the second of my first two batch's which used a profile similar to this

first APA 4 weeks in bottle
ca 76.8
mg 5.7
na 8
cl 38
so4 167
hco 16

second IPA Only 2 weeks in bottle
ca 78.8
mg 5.2
na 18
cl 58
so4 155
Hco 16

the first batch came out a little drier then i hoped for. the second one is much nicer. it came out just a touch sweeter with a hit of saltiness

 

[ajdelange]

Here's what each would give me:

2 g each, 1 oz acid malt:
Ca - 61.1
Cl - 58.3
SO4 - 67.5
Mash pH - 5.33
RA - -61.9

3 g Gypsum, 2 g CaCl, 0.5 oz acid malt (to reduce the lowering of pH since more Ca):
Ca - 75.2
Cl - 58.3
SO4 - 101.2
Mash pH - 5.34
RA - -61.5

I'm leaning toward the latter, with slightly higher Ca and SO4... Think it'll make much difference?

I'd expect that the difference in sulfate levels would produce noticeably different beers. I always recommend that one start with low sulfate and 'taste up' in the glass but you don't have to do it that way.

But if I tried changing only one thing at a time, it would take me the better part of a year to get to where I want to be (I only brew about once a month).

Another musical analogy: A stranger lost in Manhattan approaches a gentleman he assumes to be a native and asks "How do I get to Carnegie Hall?" The New Yorker answers "Practice, practice, practice!". So is it with beer. The tasting in a glass method lets you learn lots more from each brew than brewing, incrementing a salt and brewing again. But the principle remains. If you want to make good beer you have to brew a lot.

 

[ajdelange]

That sort of fits expectations. Additional chloride generally makes beer taste all around better: smoother, fuller bodied, sweeter. OTOH the reduced sulfate make hops bitterness 'finer'. I can not assert that this is what is happening here but it is what one might expect to happen with these profiles.

 

[Ohbsolutely]

My advice to you would be to treat all the water at once using 1/2 tsp of CaCl2 and 1/2 tsp of gypsum. Right now you need to be learning the fundamentals of all grain brewing and not the details of water management. This simple recommendation will give you a good beer...As this simpler recommendation lowers calcium and the specialty malts have so little influence because they are used in modest quantity I would suggest some sauermalz - perhaps 1%.

AJ, sorry to bug you on multiple threads, but would a 10 gal blonde ale also benefit from this simplistic approach of 1 tsp CaC12 and 1 tsp gypsum and acid malt around 1% (all distilled water)?

 

[ajdelange]

The object of the Primer was to have as universal a recommendation as possible but there are, of course, limitations to the 'one size fits all' approach. I haven't had feedback that says 'I tried your stupid Primer and my beer came out a dumper' (yet) so I can tentatively say that yes, this recommendation (or rather the recommendations of the Primer which recognize the need for some variation with style) should work for most any beer.

 

[FatsSchindee]

Most do read 0.3 low but someone just posted about some he was using that read high. I don't really know, at this point, if pH strips are worse than no measurement but I'm coming around to that POV.

Well, my ColorpHast strips (4-7) finally showed up in the mail, a week after brew date! (Better late than never, as the saying goes...) Last week was the best time my schedule allowed for brewing, so, with the above quote in mind, I brewed my APA with the RO water adjustments anyway. I ended up going with the 3 g Gypsum and 2 g CaCl, along with 0.5 oz acidulated malt. Brewer's Friend calculated 5.34 for my mash pH with that grain bill and adjustments.

Here's a question: does pH change much over time, with the only other change being temperature? Thinking ahead, I saved a sample of the mash wort (taken about 30 min in, after it should have stabilized) in a shot glass, covered it in Saran Wrap, and put it in the fridge. When my strips arrived today, I took it out, let it warm to room temp, and dipped a strip. The color (as seen on the pic) looks closest to the 5.0 reference to me, but if they do indeed tend to run 0.3 low (and if the mash pH of the wort sample didn't change during a week in the fridge), that would be just about right for what I was attempting to hit...

The beer has been in primary for a week, and I'm getting ready to dry-hop it soon. I'll get a taste when I get a gravity reading, and then I'll have a better idea how things went, I guess.

 

[DaveHunter5]

This is not an advertisement for pH meters but I think it is pretty clear why they are so valuable.

AJ, what pH meter do you recommend?

 

[ajdelange]

I have always used and only really have experience with Hach meters which are generally well out of the range of what home brewers want to spend. I also bought a pHep unit just to see what it was possible to do for under $100. I found it adequate but not very stable. When I realized that pHep stands for 'pH - electronic paper' I took that to mean that the manufacturer was not making unreasonable claims for these. They can be used for brewing but one must learn the extent of the instability of the particular unit he has and set calibration frequency accordingly. I also keep an eye out for reports of pH meter experiences here and the ones that seems to get beat up on the most are the Milwaukee meters. I am occasionally asked by members of my brew club to check meters most of which are the $50/60 ones. Their price tags are pretty good predictors of their performance.

All in all I can't really recommend anything I've mentioned: the lower priced units because of instability and the stable ones because of price. One possible exception is the Hach (rebranded) PH-1 which uses your iPhone as the 'meter'. It seems quite stable though the junction is simple piece of rag. It is great for general use but I'm not sure how it would stand up to the rigors imposed by sugar and protein laden wort. It is $300.

Hope springs eternal. Hach has a new pen - type unit for just over $100. Their slick sheet talks accuracy and precision of 0.01 and goes on and on about measurements in which one can have confidence. Maybe I'm seeing what I want to see (or what they want me to see) but I've invested the $110 to see for myself. It's in the mail so I should have it soon. I'm somewhat hopeful that this may turn out to be the Philosophers Stone that we all have been hoping for but I'm not holding my breath.

 

[mabrungard]

I keep seeing report after report from brewers with those all-in-one pH meters regarding their poor performance or longevity. Conversely, I have found that my Milwaukee MW101 meter to be a trooper. The lack of ATC in this model helps reduce cost and the lack of ATC is not an issue since that feature is nearly useless in brewing.

The other good thing is that this meter uses a replacable probe with an industry-standard BNC connector. Since the quality of measurement is really dependent upon the probe, the ability to eventually buy an even better probe someday should also be a bonus.

The Brungard recommendation is on the MW101. Take that for exactly what its worth

 

[Blarneybrew]

I'm somewhat hopeful that this may turn out to be the Philosophers Stone that we all have been hoping for but I'm not holding my breath.

I was quoted today on a hach at $93. I'm getting a discounted price from the supplier, so it's probably the same one you ordered. I'll wait for your feedback before buying, thanks

 

[ajdelange]

I was going to, but forgot, to mention that frequently a 'Milwaukee is a POS' post is followed by an almost passionate defense from someone who really likes them, as is the case here. It's sort of like a Yelp review with an average of 2 and a half stars but all the reviews are either 5 stars or 0 stars. At the price point I wouldn't expect much but I have never had my hands on one.

A comment about ATC is in order. A meter must compensate for temperature as the response of an electrode is directly proportional to it. It is impossible to build a pH meter without it. If the meter is a modern digital meter it contains an (analog) instrumentation amplifier (low drift but more important very high input impedance), and a A/D converter. The A/D converter (input is multiplexed between the pH electrode and an RTD or thermister used to measure temperature. The temperature compensation is done automatically because there is basically no other way to do it. It is inherent in the algorithm that turns millivolts into pH readings. Computation of slope and offset from buffer readings also become automatic because there is really no other practical way to do it. Buffer mV and temperature readings are inserted into equations and slope and offset fall out. In older meters slope and offset aren't actually calculated but rather the gain of the analog amplifier is adjusted and an offset voltage is applied to its input to try to match the gain and offset of the amplifier to the electrodes characteristics. Both gain adjustment and offset voltage selection are done by means of analog potentiometers. Temperatures must be read by an external thermometer and the amplifier gain trimmed according to the temperature using a third potentiometer. The output of the chain of gain controlling and offseting analog electronics is connected to a digital voltmeter - no processing other than table lookup conversion between mV and pH. There is a reason modern equipment (communications, entertainment, medical, laboratory instrumentation, navigation....) is digital. Digital equipment is immune to the noise, thermal drift, mechanical and aging induced instabilities of analog circuits. Is ATC necessary in brewing? That depends on your perspective. If you are willing to bring buffers and samples to exactly the same temperature for each calibration/measurement set it is not. If you want the freedom from worry about temperature control but want to maintain the accuracy which your meter should deliver (that accuracy should be determined by your buffers, not your instrument) then you do need ATC. Much more important than whether you actually need it or not is the fact that its absence tells you that the meter is analog (the pots on the face of it tell you the same thing). I don't recommend analog meters today as modern digital designs pretty much leave analogue circuitry in the dust. The difference between an analog VHS camcorder and a modern HD AVC one that writes to SD cards is more dramatic than the difference bewtween analog and digital pH meters but I hope you get the point. Analog pH meters (and VHS camcorders) are becoming rare and will not be available soon. There is no market for them.

This is not, to my way of thinking, a contest between the Milwaukee units and the pen types. I don't recommend either. pH meters is an excellent example of the old saw: 'The bitterness of poor quality remains long after the sweetness of low price is forgotten'. I am not recommending the new Hach unit either. I am, of course, hopeful that it will be the $110 breakthrough device we all want but the realistic expectation is that it won't be.

I referred to achievable accuracy earlier. With ±0.02 pH technical buffers and 0.5 mV voltage and 0.5°C reading accuracy you should be able to get slightly better than 0.02 pH reading accuracy at mash pH's given a proper calibration and ATC (or strict temperature control). Do we need that? Not if the goal is nothing more than to get mash pH betwen 5.4 and 5.5. But if we want to see the effects of a couple mVal extra calcium in the mash liquor, for example, then we do.

 

[ajdelange]

I was quoted today on a hach at $93. I'm getting a discounted price from the supplier, so it's probably the same one you ordered. I'll wait for your feedback before buying, thanks

Rats. Cost me $110 but I get a free holiday gift!

 

[grathan]

I've got the MW101 as well. It doesn't perform well for RO readings. I wonder if the Hach is any better. I put the meter in RO water after calibration and it jumps to 12.5 then slowly dives to 6.5 over 5 minutes.


The temperature adjustment seems unimportant in brewing imho. Who wants another probe dangling around while trying to take PH measurements. You'll also need a bigger sample vessle to fit the 2nd probe.
Its not like anyone is gonna pop their expensive probe into boiling water and If you look at the compensation chart for the working range you'll see it's a matter of couple hundredths of a point. Same thing with the manual temperature dial on the mw101, you can crank it from one extreme to the other and it barely changes the ph.

 

[ajdelange]

I've got the MW101 as well. It doesn't perform well for RO readings.

RO water is low in ionic strength (it has few ions in it) and thus has low electrical conductivity ('TDS' is really a conductivity measurement). pH measurement requires current flow, feeble though it be, so these conditions are a challenge even for good meters so it is usually done using special buffers with ion strength adjusters (that don't effect pH) and a chamber that isolates the sample from the air.

I wonder if the Hach is any better.

I do too - that's why I sprung the $110. It wasn't the holiday gift. Given the price point we can't expect too much. I certainly hope it will be better than what 0 star reviewers post about MW101. We'll see how it compares to the acolytes' reports.

I put the meter in RO water after calibration and it jumps to 12.5 then slowly dives to 6.5 over 5 minutes.

That might even be normal for a low ionic strength situation. The early readings are dominated by noise and, as CO2 dissolves and some conduction can take place the readings settle out. So don't fault the unit for erratic readings in RO or DI water. The question is how stable is it in a mash sample or, even more fundamentally, how stable is it in one of its calibration buffers. Calibrate the meter, then return the electrode to the 4 buffer and record the reading of the meter every 5 minutes for an hour or more. If the readings are randomly distributed about 4 with none outside the band 3.89 - 4.03 then you are realizing the potential of technical buffers and your meter is in good shape. If the readings are randomly scattered in a band such as 3.86 to 4.06 or if there is a trend over time (at the beginning of the hour readings are close to 4.01 but at the end they are clustered around 4.1) then there is a 'problem' with the meter. The problem may be something repairable (as by cleaning the junction or bulb) or it may be that the design of the electrode is such that it simply is not stable. The latter is usually the case with the low dollar meters.

I'll hazzard a guess as to what may be involved here as it is a fairly common practice in industry. Manufacturer A and Manufacturer B both make relativity condensers that use widgets as a key component. Manufacturer C makes widgets. Because of process variations, about 10% of the widgets exhibit superior performance, 20% exhibit good performance, 20% adequate performance and the other half poor performance that may be acceptable for non demanding applications. C tests each widget that comes off the production line and sorts them by performance. He labels the top performing decile 'Platinum' and sells them at premium price. If he is clever, though, he will offer the next two deciles as 'Gold' and the next two as 'Silver'. Manufacturer B makes 'student' or 'economy' relativity condensers and buys the lowest 5 deciles for inclusion in his devices. A related scenario is that Manufacturer B makes his own widgets using a less robust, but cheaper, process, doesn't sort them and puts them all into his units. As they are of variable quality there is a chance you may get a really good one but it is more likely that you won't. This sort of fits what I see reported on Milwaukee meters (which I think are made in Romania). Some report multiple electrodes, multiple return trips to the distributor, replacement units, all junk. Others offer glowing reports.

The temperature adjustment seems unimportant in brewing imho. Who wants another probe dangling around while trying to take PH measurements. You'll also need a bigger sample vessle to fit the 2nd probe.
Its not like anyone is gonna pop their expensive probe into boiling water and If you look at the compensation chart for the working range you'll see it's a matter of couple hundredths of a point. Same thing with the manual temperature dial on the mw101, you can crank it from one extreme to the other and it barely changes the ph.

That's not an unreasonable opinion to hold depending on how much of an 'accuracy freak' you are (guess where I fall in the spectrum). The worth of ATC (or indeed any kind of TC) depends on how far you are from the isoelectric pH.
The correction is (1 - Ts/Tc)(pHi - pHs) where s means sample and c means calibration (if the calibration buffer temperatures were not the same it's a bit more complicated) The temperatures are in Kelvins. So if you calibrate at 20 °C and measure at 25 °C and the sample pH is 5.4 the correction is, assuming the isoelectric pH is 7,

(1 - (273 + 25)/(273 + 20))*(7 - 5.4) = -0.027 pH

That's not a whole lot of pH but, as I said in my last post, with technical buffers you should be able to realize accuracy of better than 0.02 pH and that, RSS's with the error incurred by ignoring TC gives an overall accuraccy of 0.034 pH. If that's a don't care then don't worry about it. As I also said in the last post the absence of ATC is not so much of a concern as the fact that it signals that TC is done is analog circuitry.

You don't need a larger vessel to hold the temperature probe because in current designs the RTD is incorporated into the electrode body.

 

[ajdelange]

I wonder if the Hach is any better.

In it's first stability test run it looks very, very good. I am with a bit of caution in reserve, amazed and delighted. The plot below shows the difference between the calculated pH of 4 buffer used for calibration and the pH meter reading with temperature of the sample also indicated. The buffer pH values for each temperature were calculated from a fit to the buffer's calibration data table and the pH readings are compensated by the meter's ATC. Function. These data are particularly easy to collect as the sample with this meter is placed in the cap which protects the electrode when the meter is not in use. As this cap is tightly sealed with an O-ring all I had to do was calibrate (with 7 and 4 buffers) leave the 4 buffer in the cap and turn the thing on when I wanted a reading. The data set includes an unintentional 'drop test' from waist level to tile floor. This didn't disturb the readinds (whew). The 'manual' which doesn't come with the meter (you have to get it from Hach's website) states that accuracy is 0.01 pH. The box it came in calls it 0.02 pH. The rms error of the data in the plot is 0.012 pH so it is close to the optimistic spec and better than the pessimistic one. So tentaively, barring infant mortality, short electrode life (replacement $67) large number of bad units going out, junction easily fouled by protein.... it looks as if this may be the under $100 (Balrneybrew got quoted $93) meter that we have been looking for. I'll note that the box mentions brewing as an application. Another interesting note is that I cannot find anything in the manual or quick start guide that suggests anything beyond just sticking the cap on for storage i.e. no storage solution.

Looks good!

 

[jsguitar]

AJ, would you mind posting your thoughts on the hach pen ph meter once you've used it for a bit? I might be interested in one if it passes muster. Thanks.

 

[ajdelange]

See #24. Tentative at this point of course but it looks very good.

 

[jsguitar]

See #24. Tentative at this point of course but it looks very good.

Doh! I hadn't read that post yet.

It is looking good indeed. Very encouraging!

Thanks!

 

[Glynn]

I gotta tell ya AJ when yo and that other water dude start talking about water my eyes start to glaze over. I wish i had a clue as to what your talking about. When I look at your graph I'm trying to connect the dot and make a snowman

 

[molson]

Can someone post the model number or link to the hach pen pH meter, I can't seem to find it on their site.

 

[ajdelange]

http://www.hach.com/pocket-pro-ph-tester-with-replaceable-sensor/product?id=17990686211
but don't necessarily get it from them as apparently they can be had for under $100.

 

[molson]

http://www.hach.com/pocket-pro-ph-tester-with-replaceable-sensor/product?id=17990686211
but don't necessarily get it from them as apparently they can be had for under $100.

Cool, thanks!

 

[jsguitar]

I was quoted today on a hach at $93. I'm getting a discounted price from the supplier, so it's probably the same one you ordered. I'll wait for your feedback before buying, thanks

Blarneybrew, would you mind sharing more about where/how you got this deal? I'm not finding the meter listed anywhere other than the hach site. Thanks!

 

[ajdelange]

More good news on this meter. Calibration hangs in within a couple of hundredths over days but after a few hours (and I haven't been able to figure out how many) a ? appears on the display's calibration symbol reminding you that you should recalibrate. At this point I think that the unit I have would not need to be recalibrated during a typical brew day.

In another stability run I wanted to explore the question of the unit's isoelectric pH. This isn't something that most users even know about let alone worry about so before diving in let me say that I think the data presented here represent very good performance on the part of this meter.

The difference between buffer pH and meter reading over time for this data set are in the first graph below. You will notice the ramping up and down over time which is clearly correlated to temperature. This is indicative of an isoelectric pH which is not equal to 7 (the desired value and the value it must have for ATC to be completely effective). When it isn't one either must determine what the isoelectric pH (pHi) is and correct for that or limit the temperature range over which measurements are made. This is what I refer to as 'not overworking' ATC. In this data set which spans 9 - 32°C the overall rms error is 0.023 pH (0.003 more than the accuracy specified on the box the meter came in) but over the region 15 - 25 °C it is 0.0105 (which is 0.0005 more than the manual's claimed accuracy for same temperature measurements).

The second graph shows the errors (solid black circles) plotted against temperature and the correlation is very plain there. The solid line is a model of how pHi causes ATC to induce error and is drawn for the value of pHi which minimizes the error. This is an estimate of pHi which, for the unit I have in hand, is 7.9. This does not mean that your meter, should you buy one, will have a pHi of 7.9. It is rare that pHi is specced as no meter I have ever seen allows entry of this parameter into the meter's algorithm which is a pity as it would make ATC much more effective. Expensive electrodes have a pHi spec of 6.5 < pHi < 7.5 i.e. a 1 pH wide band about 7 and so this meter doesn't meet that though it's still not bad. Note that the electrode I have (same manufacturer) which specs (6.5 < pHi < 7.5) cost three times what this whole meter costs but doesn't meet that spec either but as I have been using it since 2009 I can't complain.

Given an estimate of pHi we can correct readings obtained from the meter for it quite simple. The hollow squares show the errors associated with meter reading that have been so corrected. Their rmse over the whole temperature range is 0.011 which is 0.001 worse than the manual's claim for readings all made at the same temperature as the cal. A more telling test would be to use the pHi value determined from this data set to correct a different data set.

At this point I am still impressed. Before I can unconditionally recommend this unit it is only reasonable to want to have more experience with it and to be sure that the unit I have is not exceptional IOW that it isn't like the Milawuakees discussed earlier that have some 5 star reviews but a whole bunch of 0 stars too. At this point I'd feel safe in recommending it with the caveat that it is new and the experience base narrow.

 

[mabrungard]

Very good news, AJ. Glad to see that meter performing well. I tried to ascertain the junction type for that meter, but couldn't find it mentioned on the Hach website or in their manual.

In following up with discussions on pH meters, I found that when dealing with 'dirty' water, it is best that the probe have a Double-Junction instead of Single-Junction. That was confirmed by my wastewater equipment supplier. So, I'm hoping that the Hach meter is a double-junction type. I was able to confirm that the Milwaukee MW 101 comes with a double-junction probe. Now I'm curious if those meters that seem to be more problematic are double- or single-junction probes?

On a related note, I see that you can pick up a Chinese probe with BNC connector for as little as $14. However, I'm pretty sure they are single-junction probes. I do see double-junction probes w/ BNC connector for under $40. I suppose that makes sense since the MW 101 meter and probe can be had for around $80. Don't scrimp here, get a double-junction probe with your meter.

 

[ajdelange]

Very good news, AJ. Glad to see that meter performing well.

It's hard to stifle excitement but we really need to withhold final judgement until more brewers have tested them or at least worked with them.

I tried to ascertain the junction type for that meter, but couldn't find it mentioned on the Hach website or in their manual.

They aren't very forthcoming about design, that's for sure. In fact the manual isn't a font of information on much of anything. Nothing in it on long term storage, for example. I can't even figure out the intended market. Manual says 'general water testing'. What does that mean? Streams and rivers, waste and potable I guess. The box listed broader applications such as food industry, water water, brewing, beverages...

As nothing sticks through the face but the bulb, the junction and the RTD it is impossible to see anything of the construction. So no help there. If the junction fouls or the reference electrolyte gets contaminated in the brewing application that will show up pretty quickly and the grade will go from A+ to D.

In following up with discussions on pH meters, I found that when dealing with 'dirty' water, it is best that the probe have a Double-Junction instead of Single-Junction. That was confirmed by my wastewater equipment supplier. So, I'm hoping that the Hach meter is a double-junction type. I was able to confirm that the Milwaukee MW 101 comes with a double-junction probe. Now I'm curious if those meters that seem to be more problematic are double- or single-junction probes?

Brewing is an application that traditionally has required double junction references because of the proteins which can precipitates protein/silver complexes with the traditional silver/silver chloride reference one sees described in textbooks. But do these meters have silver/silver chloride references? Clearly the art in electrode manufacture has advanced tremendously in the last few years and improved references are, to my way of thinking, a major part of that story. Ten years ago if you had a problem with an electrode it was the junction. That doesn't seem to be the case anymore.

I'll note that the electrodes I have used with great success in the brewery itself (stable and long lived - over three years) are not double junction (they are clear walled and I can see the internal construction in those) nor is the one I use in the lab (since 2009) nor is the one that works with my iPhone (go ahead and laugh, but I used it to shock my well, test its water and clean out scaling in my on-demand water heater this summer).

I don't necessarily hope the reference is double junction so much as I hope that whatever it is it represents an effective solution to the problem the double junction strives to solve: control of diffusion potential and prevention of contamination of the reference electrolyte with sample. It either does or it doesn't. We shall see.

On a related note, I see that you can pick up a Chinese probe with BNC connector for as little as $14. However, I'm pretty sure they are single-junction probes. I do see double-junction probes w/ BNC connector for under $40. I suppose that makes sense since the MW 101 meter and probe can be had for around $80. Don't scrimp here, get a double-junction probe with your meter.

In a traditional single junction design the reference electrode (a platinum wire dipped in silver chloride) is immersed in a solution saturated with silver chloride and potassium chloride an that opens to the sample through a frit of some sort. In a double junction design that frit opens into a second tube full of potassium chloride solution and that tube has a frit that is open to the sample. The electrode is thus twice isolated from the sample. Other chemistries are possible but this is at the heart of the electrode. The glass bulb part is the simple bit. Anyway, going to a double junction with today's technologies shouldn't add much to the cost of manufacturing an electrode. 'Double junction' does sound good though, doesn't it?

The visible junction on the Pocket Pro + is not like anything I have seen before. It appears to be 3 mm in dia. with something about 1.5 mm in dia protruding from the center. Ceramic? I have no clue. Examination under a low power (dissection) microscope doesn't reveal any pores but the angle required to get it onto the stage makes it hard to see.

In case I failed to mention it in earlier posts the cost of a replacement electrode for this meter is $67.

Also speaking of earlier post's: I made a sign error in calculating pHi so the pHi needs to be reflected about pH 7. It is, thus 7.9 not 6.1 for this S/N. An that is more than the specified 6.5 < pHi < 7.5 spec for the $300 electrode I was thinking of. The post has been corrected.

 

[grathan]

Any comments on it's RO water performance yet?

 

[ajdelange]

O, yes, forgot - I did do one quick test. As I noted in an earlier response RO is difficult to test because of low ionic strength but this unit seems to do OK. It has an advantage in that the sample goes into the cap which then plugs onto the meter body. An O-ring seals it on. The sample I tested initially read 5.67 (which is very close to the theoretical pH of DI water exposed to air with partial pressure of CO2 0.03 ATM) and then migrated up to 5.73 and then pretty much stayed there or an hour or so after which I discarded the sample. I didn't see the point in doing an elaborate test similar to the buffer tests. This is, IMO, completely normal and acceptable behaviour.

 

[ajdelange]

An additional thought on the RO water performance. RO water has very high resistivity and stable readings in such a medium would suggest that the membrane (glass) has relatively low impedance and the meter electronics meter relatively high. Lower input impedance in the Milwaukee unit might be an explanation.

With respect to the new Hach. The manual says nothing about the storage requirements and that is, as I have just verified with them on the phone, because there is nothing to say. Rinse it off and put the cap on is all there is to it. If it isn't used in a while just rehydrate the bulb for a couple of minutes. So you don't have to buy storage solution.

 

[mchrispen]

With my Milwaukee MW100, RO takes much longer to measure, but I don't see a lot of variability. I do have some (mostly bicarb) TDS, so perhaps this can be disqualified. I generally move the probe around for 10-15 seconds, look at the reading, and swirl the probe again - and seldom see much variation. The MW100 doesn't have ATC and I don't see the jittery responses I saw with a cheaper pen-style meter with ATC. Of course, my meter suffers with only +- 0.1 pH accuracy. Still I am very happy with it - especially compared to my old meter. Easy to calibrate with the manual knobs.

I don't see much specific probe information on their website, just this:

MW100 and MW101 are supplied complete with a
MA911B/1 pH electrode, pH 7.01 20 mL sachet of calibration
solution, calibration screwdriver, 9V battery and
instructions.
MW102 is supplied complete with a MA911B/1 pH electrode,
MA830R stainless steel temperature probe, pH 4.01
and pH 7.01 20 mL sachet of calibration solution, 9V battery
and instructions.

It appears to be the same probe regardless of the meter body (MW100, 101, 102).

With room temperature mash, the reading only takes about 5 seconds, and again, I will remove the probe, then reinsert and stir. If the reading is off - I continue until the readings stabilize. The only time it seems to be problematic is when I have a lot of grist material in the sample, especially oats/rye/wheat. I have taken to filtering through a paper towel, then testing.

Maybe I have gotten lucky.

 

[Blarneybrew]

Blarneybrew, would you mind sharing more about where/how you got this deal? I'm not finding the meter listed anywhere other than the hach site. Thanks!

I'll get back to you on it. I got a pricing through a water supplier's contact, and I never followed up on it as I was waiting for aj's feedback. This is all assuming it's the same tool as his also. It probably is.