got a pH meter. need help!

[tgmartin000]

So i got a Milwaukee 102 pH meter, and have been using it for about 6 months. It works great, but I wish the temp reading was in farenheight. After getting the hang of it, I have a question.

Is there a way to calculate acid or alkalinity additions if I miss my desired pH?

The first few times I used it, when I went to acidify my sparge, I overshot and got a sparge water pH of like 4. Then I added lime. Oops. Now too high, like 8. Add acid. Too low. So on and so forth for a half hour.

Today my mash pH measured like 5.8. I added lactic acid, but could never get my pH into the 5.4 range. Any help? I calibrate my meter every time.

Also, on today's black ipa, with 1.25 lb of midnight wheat, brun water said I needed 5.7 g each of chalk and pickling lime, 700 mg/l alkalinity to counteract the dark malt. This is what caused the mash pH to be high. Will this beer taste like I'm eating chalk?

 

[mabrungard]

?? How are you calculating and adding your mineral and/or acid additions? If you overshot the sparge pH, that likely means that you have incorrect information on your water or on your acid. Or were you using water like RO or distilled water that didn't need to be acidified in the first place?

I'm assuming you then 'chased' the pH by adding indiscriminate amounts of lime or acid? As you found, it is a foolish endeavor.

Hmm? 700 mg/l alkalinity. That sure is a lot. I can only assume that the midnight wheat was a pretty substantial percentage of the grist, like 20%?

How are you adding these acid or mineral additions? Unless you are recirculating the wort through the mash, there is little hope that you are achieving a good mixture. The only way to assure that minerals and acids are well distributed is by either adding them to the water before adding any grain and making sure they are fully dissolved or by recirculating the wort through the mash, like with RIMS or HERMS. Mixing the mash has been proven to have low effectiveness.

If you used a good dose of chalk to add alkalinity in addition to the lime, you raise a curious debate. Since chalk has been proven to NOT dissolve nor add much of its alkalinity to a mash, the fact that the pH overshot doesn't sound possible. Something is sounding fishy.

 

[soccerdad]

In chapter 15 of How To Brew (free online edition), Palmer offers a spreadsheet to assist in water calculations - free download I think

 

[ajdelange]

Is there a way to calculate acid or alkalinity additions if I miss my desired pH?

Yes.

The first few times I used it, when I went to acidify my sparge, I overshot and got a sparge water pH of like 4. Then I added lime. Oops. Now too high, like 8. Add acid. Too low. So on and so forth for a half hour.

There are two things you can do if you overshoot (pH too low) with an acid addition.
1) Do nothing
2) Remove 10% of the treated water and replace it with untreated water. You have just removed 10% of the acid you added. The pH will go up. Still too low? Do it again. You have just removed 9% of the original acid addition. Repeat until you get the pH you want or close to it.

With respect to 1): Suppose you do undershoot and hit pH 4. That's really not not a problem. There will be 0.1 mEq/L (5 ppm as CaCO3) acidity from the extra acid. In addition to that there will be a tiny bit of acidity from carbonic acid but most (99%) of the bicarbonate in your original water will have been converted to CO2 and removed. At pH 4 the carbonic acid content in equilibrium with the air is 0.012 mEq/L and, as in converting to bicarbonate at mash pH the acidity is about .112 mEq/mmol the acidity from carbonic acid is only 0.011 mEq/L. Just be sure to agitate the water to let the CO2 out if you elect option 1).

Today my mash pH measured like 5.8. I added lactic acid, but could never get my pH into the 5.4 range. Any help? I calibrate my meter every time.

Does this mean that you added acid and could not get it down to pH 5.4 or that you undershot and could not get it back up to pH 5.4? What usually happens with acid is that the pH drops alarmingly as the acid mixes with the water and then rises over 10 - 20 minutes as the acid accesses the grain particle interiors and reacts. Going the other way with lime takes time - it reacts more slowly. For emergency pH adjustment sodium bicarbonate is probably the best bet. It is very soluble and goes into action quickly compared to lime. Chalk is even worse than lime. The chances of getting a good upward pH adjustment in reasonable time are pretty small unless you have made a test mash. Take a pound of grist, hit it with your treated water and measure the pH. Adjust the pH with diluted lactic acid or a dilute solution of sodium bicarbonate. When you reach the desired pH take note of the amount of solution you used and scale that to the full brew (taking dilution factors into account). If you want to take this a step further divide the amount of acid or bicarbonate you used by the pH shift to get a rough estimate of the mash's buffering capacity (cc/pH). Then, when doing the full scale brew if you are off by delta_pH the amount of solution to correct that is delta_pH*(cc/pH)*scale_factor. If you have done the test mash right you should be pretty close.

Also, on today's black ipa, with 1.25 lb of midnight wheat, brun water said I needed 5.7 g each of chalk and pickling lime, 700 mg/l alkalinity to counteract the dark malt. This is what caused the mash pH to be high. Will this beer taste like I'm eating chalk?

You must have entered the numbers wrong but yes, I'm told that beers made with that much chalk taste chalky.

 

[tgmartin000]

?? How are you calculating and adding your mineral and/or acid additions? If you overshot the sparge pH, that likely means that you have incorrect information on your water or on your acid. Or were you using water like RO or distilled water that didn't need to be acidified in the first place?

I'm assuming you then 'chased' the pH by adding indiscriminate amounts of lime or acid? As you found, it is a foolish endeavor.

Hmm? 700 mg/l alkalinity. That sure is a lot. I can only assume that the midnight wheat was a pretty substantial percentage of the grist, like 20%?

How are you adding these acid or mineral additions? Unless you are recirculating the wort through the mash, there is little hope that you are achieving a good mixture. The only way to assure that minerals and acids are well distributed is by either adding them to the water before adding any grain and making sure they are fully dissolved or by recirculating the wort through the mash, like with RIMS or HERMS. Mixing the mash has been proven to have low effectiveness.

If you used a good dose of chalk to add alkalinity in addition to the lime, you raise a curious debate. Since chalk has been proven to NOT dissolve nor add much of its alkalinity to a mash, the fact that the pH overshot doesn't sound possible. Something is sounding fishy.

Martin -

I'm using BrunWater. Usually it's decent, but for this beer, it was significantly off. Here's my grist:

12.25 lb Maris Otter
2 lb rye
1.25 lb Midnight wheat
1 lb Munich 20
0.5 lb carapils

I add my salts to the mash/sparge water as it's warming up. In this case, since I overshot on my mash pH, I was adding acid to the mash and stirring. I do start with distilled water.

With my sparge water, I'll add gypsum, epsom salt, and calcium chloride to the desired ratio. Even then, I've found that the pH is usually just over 6.0.....now that I've got the sparge technique down, I'll add about 2 drops of lactic acid to get it to about 5.7.

 

[tgmartin000]

Yes.



There are two things you can do if you overshoot (pH too low) with an acid addition.
1) Do nothing
2) Remove 10% of the treated water and replace it with untreated water. You have just removed 10% of the acid you added. The pH will go up. Still too low? Do it again. You have just removed 9% of the original acid addition. Repeat until you get the pH you want or close to it.

With respect to 1): Suppose you do undershoot and hit pH 4. That's really not not a problem. There will be 0.1 mEq/L (5 ppm as CaCO3) acidity from the extra acid. In addition to that there will be a tiny bit of acidity from carbonic acid but most (99%) of the bicarbonate in your original water will have been converted to CO2 and removed. At pH 4 the carbonic acid content in equilibrium with the air is 0.012 mEq/L and, as in converting to bicarbonate at mash pH the acidity is about .112 mEq/mmol the acidity from carbonic acid is only 0.011 mEq/L. Just be sure to agitate the water to let the CO2 out if you elect option 1).



Does this mean that you added acid and could not get it down to pH 5.4 or that you undershot and could not get it back up to pH 5.4? What usually happens with acid is that the pH drops alarmingly as the acid mixes with the water and then rises over 10 - 20 minutes as the acid accesses the grain particle interiors and reacts. Going the other way with lime takes time - it reacts more slowly. For emergency pH adjustment sodium bicarbonate is probably the best bet. It is very soluble and goes into action quickly compared to lime. Chalk is even worse than lime. The chances of getting a good upward pH adjustment in reasonable time are pretty small unless you have made a test mash. Take a pound of grist, hit it with your treated water and measure the pH. Adjust the pH with diluted lactic acid or a dilute solution of sodium bicarbonate. When you reach the desired pH take note of the amount of solution you used and scale that to the full brew (taking dilution factors into account). If you want to take this a step further divide the amount of acid or bicarbonate you used by the pH shift to get a rough estimate of the mash's buffering capacity (cc/pH). Then, when doing the full scale brew if you are off by delta_pH the amount of solution to correct that is delta_pH*(cc/pH)*scale_factor. If you have done the test mash right you should be pretty close.



You must have entered the numbers wrong but yes, I'm told that beers made with that much chalk taste chalky.

AJ -

In this case, I added acid to the mash, but could not get it down to 5.4. I double checked my numbers in the spreadsheet, but I'm going to check again tonight when I get home.

After my brew day was over, I tasted the hydrometer sample, and the beer does taste chalky, but this beer always tastes kinda chalky, for whatever reason. Last year I made it without all the chalk and lime, and the chalky taste faded after a month and it turned into a gold medal winning black IPA (My first gold!). It's so bitter (100 IBU/7% ABV) it covers up my flaws, I think.

So basically I'm getting that if you undershoot your mash pH, use baking soda to try to bring it back up. If you overshoot, unless you're using a recirculated system, you're kinda hosed, it sounds like. Dammit.

 

[tgmartin000]

I think I see my error. I entered midnight wheat as base malt (since wheat is a base malt). When I changed that to a roast malt, my required alkalinity addition went waaaaaaay down.

Martin, I assume in this case midnight wheat should be entered as a roast malt? Set to roast malt, I only need 135 mg/l alkalinity to hit a 5.4 mash pH.

Looks like this batch might be a dumper. There goes $60 worth of hops.

Also - should I not even bother using chalk? Just stick to pickling lime and baking soda?

 

[ajdelange]

So basically I'm getting that if you undershoot your mash pH, use baking soda to try to bring it back up. If you overshoot, unless you're using a recirculated system, you're kinda hosed, it sounds like. Dammit.

I wouldn't go that far. The real message I'd like you to get is that when doing a beer you have never done before or that differs appreciably from other beers you have done before, do a test mash. It can save you a lot of grief.

If you undershoot (pH too low) correct with a sodium bicarbonate solution. If you overshoot (pH too high) correct with lactic or phosphoric acid solution. In either case you should be able to move the pH though you may have aching shoulders from all the stirring. A loose mash helps with this.

I think I see my error. I entered midnight wheat as base malt (since wheat is a base malt). When I changed that to a roast malt, my required alkalinity addition went waaaaaaay down.

Something wrong there. Highly colored malts are more acidic than base malts. If you add more acid to a mash you will require more alkalinity.

 

[mabrungard]

I think I see my error. I entered midnight wheat as base malt (since wheat is a base malt). When I changed that to a roast malt, my required alkalinity addition went waaaaaaay down.

Martin, I assume in this case midnight wheat should be entered as a roast malt? Set to roast malt, I only need 135 mg/l alkalinity to hit a 5.4 mash pH.

Looks like this batch might be a dumper. There goes $60 worth of hops.

Also - should I not even bother using chalk? Just stick to pickling lime and baking soda?

OMG! $60 in hops! Do not dump that beer. Use it to blend with other beers to use it up. It may not be that bad.

Chalk is a waste of time and generally should not be used in brewing. Baking soda has proven to be very useful and its alkalinity content is always stable. For minor to medium alkalinity additions, baking soda is a pretty good choice. Since you only add it to the mashing water, the high sodium that might be produced in the mash will be diluted when the sparging water is added.

Sorry about the miss-entry of the grain type for that roasted wheat. The supporter's version of Bru'n Water has a bunch of warning mechanisms to help alert the brewer what they have entered and when some things could lead to trouble. It also automatically calculates that diluted sodium content when you add baking soda only to the mash.

 

[tgmartin000]

I wouldn't go that far. The real message I'd like you to get is that when doing a beer you have never done before or that differs appreciably from other beers you have done before, do a test mash. It can save you a lot of grief.

If you undershoot (pH too low) correct with a sodium bicarbonate solution. If you overshoot (pH too high) correct with lactic or phosphoric acid solution. In either case you should be able to move the pH though you may have aching shoulders from all the stirring. A loose mash helps with this.



Something wrong there. Highly colored malts are more acidic than base malts. If you add more acid to a mash you will require more alkalinity.

Awesome. Thanks AJ! I'm definitely going to start doing a test mash on new beers. Never thought of that. I appreciate it.

 

[tgmartin000]

OMG! $60 in hops! Do not dump that beer. Use it to blend with other beers to use it up. It may not be that bad.

Chalk is a waste of time and generally should not be used in brewing. Baking soda has proven to be very useful and its alkalinity content is always stable. For minor to medium alkalinity additions, baking soda is a pretty good choice. Since you only add it to the mashing water, the high sodium that might be produced in the mash will be diluted when the sparging water is added.

Sorry about the miss-entry of the grain type for that roasted wheat. The supporter's version of Bru'n Water has a bunch of warning mechanisms to help alert the brewer what they have entered and when some things could lead to trouble. It also automatically calculates that diluted sodium content when you add baking soda only to the mash.

Let me rephrase that - $60 in ingredients! Like I said, the chalky flavor seems to fade from this beer after a while, so I'll probably sit on it and see what happens. Although I think I am going to re-brew it. I'll ditch the chalk from now on. I'll also check out the supporter's version. Thanks Martin.

Like anything else in brewing, new equipment means a new learning curve, and I've found the pH meter is no different.