Getting poor efficiency, how to measure mash tun temperature

[guitarguy6]

Hi guys, I recently made the switch to AG brewing and am getting poor efficiency. I think it's due to the fact that my mash temps aren't being read correctly. I'm using a Homedepot 5Gallon cooler that I converted for the mash tun and was wondering what you guys recommend for monitoring the mash temp. I'm using an electric food thermometer that I picked up at Walmart for $20 and am doubting it's accuracy. http://www.walmart.ca/en/ip/stainles-steel-thermometer/6000147014497 I ordered this thermopen from amazon and am waiting to receive it http://www.amazon.ca/gp/product/B0021AEAG2/?tag=skimlinks_replacement-20 .

Most of my batches should have an OG of about 1.055 and I'm getting around 1.04 - 1.045. I mash for 1 hour at 152-154 for 60 min and then sparge with 170 water for at least 30min but it's usually around 45 min. According to my current thermometer I lose at most 2F during the hour. What's odd is on my last batch I had my mash at 153 and at the end of the hour it read 155F I have a HLT that connects to a big circle shower head that fits exactly over my mash tun so I get pretty even coverage. I have a 19 gallon kettle with a 4500Watt blichmann boilcoil that I just purchased and usually do 60min boils. I'm taking my brix reading with this refractometer http://www.ebay.ca/itm/221503392276?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 Does the temperature of the wort sample matter when taking the reading?

Example of last 5Gallon recipe: 6KG 2 Row, 0.45KG Munich, 1oz Chocolate Malt, 1oz Centennial 60min, 1oz Cascade 15min, 1oz Cascade 5min

Pic of current setup

 

[mlafnitzegger]

Lots of factors effect mash efficiency. I had issues with efficiency and look into water ph, grain crushing, temp control. If you are doubting thermometer dont buy the walmart or target digital units. I have bought five over a year and after a couple of uses they become unreliable. Finally went with thermoworks unit and I do worry about bad readings anymore. Here is a link to the one I have;
http://thermoworks.com/products/handheld/temptest2.html

 

[kaconga]

First you have to pinpoint your problem. It could be a conversion problem as you suspect or a lautering problem. This url should help.

http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency

I have been working on my efficiency lately too and I believe it is due to mash ph since my conversion efficiency was only about 85%. I want to get it up to 95% and from there I can work on my lautering efficiency to make my brewhouse efficiency close to 78%.

 

[guitarguy6]

I'm going to order some PH test strips and see what the results are. Whether I use my LHBS grain mill or my own I'm getting pretty much the same efficiency so I don't think that's the issue. I'm also going to try a 90min mash.

 

[tacks]

FWIW, unless you have time to kill and nothing better to do, go with the 90 minute mash, but anything over 30 minutes is subject to the rule of diminishing returns, your beta amylase will still be somewhat active, but you're probably only going to get a couple extra points out of that additional half hour. Your best bet is first checking and maintaining a good pH, but if your thermometer is off that would be the first thing I would take care of. If you can't reliably hit/maintain your mash temp, it's a lot harder to control other more delicate elements such as pH.

http://www.howtobrew.com/section3/chapter14-5.html

 

[guitarguy6]

I'll definitely be paying close attention to PH and temp as soon as I have the required items. There's a sticky on this forum under the all grain section where quite a few members where having better efficiency so I figured it's worth a try.

 

[bu_gee]

Thermometers are easy to check: Put it in a cup of ice water. If it doesn't read 0°C or 32°F, discard. Put it in boiling water. If it doesn't read 100°C or 212°F at sea level or your altitude corrected boiling temperature, discard.

The cheapness of the thermometer usually has less to do with inaccurate readings than does poor positioning of the probe. I think you'll find even the more expensive thermometers measure differently in different places in the mash.

 

[guitarguy6]

Thermometers are easy to check: Put it in a cup of ice water. If it doesn't read 0°C or 32°F, discard. Put it in boiling water. If it doesn't read 100°C or 212°F at sea level or your altitude corrected boiling temperature, discard.

I didn't think of trying that. Thanks for the tip. Any insight on the wort temp when I'm taking the refractometer reading?

 

[tacks]

What is your refractometer calibrated to? Mine is 70℉, it should tell you either on the literature or whoever you bought it from should be able to tell you.

 

[bu_gee]

No specific insight on the refractometer because I use a hydrometer for my density measurements. I don't know if there is a correction you have to apply for temperature using the refractometer, but I have about a 0.001 correction per 11°F I have to apply over the calibration temperature of the hydrometer.

As an example, if I measured a gravity of 1.045 at 155°F, my corrected gravity at 68°F would be 1.053.

 

[guitarguy6]

What is your refractometer calibrated to? Mine is 70℉, it should tell you either on the literature or whoever you bought it from should be able to tell you.

Literature says 20C so I think that's 68F.

 

[DrMaltyVonHopenstein]

What's odd is on my last batch I had my mash at 153 and at the end of the hour it read 155F

I recognize that one. One tip that will directly improve mash efficiency is to more thoroughly and frequently mix the mash. You need to redistribute the heat and the enzymes. Some home brewers, and certainly some pro brewers use a motorized mash mixer/stirrer to maximize this aspect of efficiency.

Why does this matter? It is very common to have hotter and cooler pockets in the mash (especially right after you dough-in), and inconsistent temps affect the starch conversion. In addition, the redistribution of the enzymes and the unconverted starches helps by simply mixing them together to allow for conversion.

*A related discovery: While doing a step-mash once (metal pot on a burner), I wanted to avoid scorching the wort on the bottom, so I used a pitcher to draw-off the hottest liquid from the bottom and then I gently poured it on top. The added benefit: my efficiency increased by about 5 points compared to a very similar recipe. Now, I try to mix the mash every 15 minutes or so and re-circulate about 2 quarts of liquid once or twice and my efficiency is consistently 80-85% for beers under 1.060.

Sparging - I started with the same sparge method too. One problem that *can* arise with a gentle fly sparge is that the sparge water is only following the same little paths of least resistance and not pushing/dissolving all of the available sugars.

 

[tacks]

Bu_gee is right about the hydrometer sliding scale in regards to temperature, you don't need one for refractometers since you can just let the wort cool to 68℉/20℃ before measuring.

 

[guitarguy6]

For some reason I was under the impression that mixing the mash a whole bunch is bad. Typically I slowly pour in the grain while a friend mixes it in the mash tun. Once we're sure it's mixed well I'll leave the thermometer in it until the temp stabilizes and I don't mix it again at all. Should I mix once or twice during the mash and again during the sparge?

 

[duboman]

First you need to take a pre- boil gravity reading to be sure you are getting that correct. If your mash/ lauter efficiency and reading are low or high then the problem is in that part of the process: crush, pH, sparge, extraction/conversion.

If that part of the process is getting the proper preboil gravity then your issue is in the boil band achieving proper volumes.

Without isolating the two separate parts of brewing you're only guessing where the issue is

 

[kh54s10]

My thoughts are to make sure you have a good crush on your grains. This is the most common source of poor efficiency.

For the mash tun, is it a water line braid inside? If so you may be getting water channeling. That would be water taking the path of least resistance thus leaving a lot of sugars behind. A false bottom could be the fix.

Stir in the grains very well, many will stir again every 15 minutes. After the first runnings, I would flood the grains with sparge water and stir very well then start the fly sparge.

I think you need to keep track of your ph though I batch sparge and don't worry about ph.


Sent from my iPhone using Home Brew

 

[guitarguy6]

Pre boil gravity is to low. In the recipe I posted I should have had a pre-boil gravity of 1.046 and I had 1.04.

 

[duboman]

Pre boil gravity is to low. In the recipe I posted I should have had a pre-boil gravity of 1.046 and I had 1.04.

That's not terrible. Evaluate your crush and confirm your temps. Also, if you are fly sparging it should take about an hour and there should always be water above the grain bed, if not your going too fast and getting a poor sparge. PH is always a factor to keep in range as well.

 

[bu_gee]

Okay, I'm new to this, so somebody check my method and math on this.

Shouldn't 6.45 kg of grain yield closer to 1.085? Here's what I did:

6.45 kg x 2.205 lbs/kg x 30 p/p/g = 427 pg
427pg/5g = 85p

I bring this up because somehow the numbers just don't look right to me.

 

[kaconga]

Okay, I'm new to this, so somebody check my method and math on this.

Shouldn't 6.45 kg of grain yield closer to 1.085? Here's what I did:

6.45 kg x 2.205 lbs/kg x 30 p/p/g = 427 pg
427pg/5g = 85p

I bring this up because somehow the numbers just don't look right to me.

Pre boil gravity would be

427/6.5 = 65.7p

Which would be 100% efficiency. So at 70% efficiency you should expect:

65.7*.7~46p

Hope that clears it up for you.

 

[guitarguy6]

Exactly what kaconga said. I estimated with %65 efficiency.

 

[bu_gee]

Pre boil gravity would be

427/6.5 = 65.7p

Which would be 100% efficiency. So at 70% efficiency you should expect:

65.7*.7~46p

Hope that clears it up for you.

The 30ppg figure I was using allegedly had an 80% efficiency built into it. At 100% I would have used 37 making the math

6.45 x 2.205 x 37 = 526pg

Also, how did you come up with 6.5gal? I thought he said 5 gal batches. But using your number:

526/6.5 = 81p

Using 70%:

81 x 70% = 57p.

That's a lot more like his number.

 

[bu_gee]

Exactly what kaconga said. I estimated with %65 efficiency.

Ah. Okay. I must have missed the 6.5 gals.

 

[helibrewer]

Does your refract have ATC? If so put a couple drops on it and wait about 30 sec to take your reading. With a 1.5Lb/qt ratio you should be able to get close to 1.080 (about 20 Brix with a refractometer) when conversion is complete. This is your first wort gravity.

If you are not getting this number or higher at that ratio, then you have conversion issues (crush, pH, temp, etc.) The link given earlier for Braukaiser will show you charts for various mash ratios and what you should be getting for conversion.

 

[kaconga]

The 30ppg figure I was using allegedly had an 80% efficiency built into it. At 100% I would have used 37 making the math

6.45 x 2.205 x 37 = 526pg

Also, how did you come up with 6.5gal? I thought he said 5 gal batches. But using your number:

526/6.5 = 81p

Using 70%:

81 x 70% = 57p.

That's a lot more like his number.

Most of us start at 6.5 gallons and boil off 1 gallon to end up with 5.5 gallons at end of boil. Then you leave behind the last .25 gallon in the kettle with the break material. And when you rack to bottle you might leave another .25 to trub. So you bottle/keg a true 5 gallons vs 4.5-4.75 gallons.

 

[duboman]

Most of us start at 6.5 gallons and boil off 1 gallon to end up with 5.5 gallons at end of boil. Then you leave behind the last .25 gallon in the kettle with the break material. And when you rack to bottle you might leave another .25 to trub. So you bottle/keg a true 5 gallons vs 4.5-4.75 gallons.

Its still a 5 gallon batch unless I'm reading your post wrong, your math should still take the 5 gallon batch size, not the preboil volume

 

[bu_gee]

Most of us start at 6.5 gallons and boil off 1 gallon to end up with 5.5 gallons at end of boil. Then you leave behind the last .25 gallon in the kettle with the break material. And when you rack to bottle you might leave another .25 to trub. So you bottle/keg a true 5 gallons vs 4.5-4.75 gallons.

Yeah. I've always heard what duboman said. In that case you should be using 6.5 for preboil but 5.5 for OG.

I guess as long as you're not comparing a preboil estimate to your OG, you should be okay.

 

[kaconga]

Pre boil gravity is to low. In the recipe I posted I should have had a pre-boil gravity of 1.046 and I had 1.04.

He specifically said it was pre-boil in this post. I see now why people would be confused. His 1.046 was pre-boil gravity projection at 65%(if I understand him) efficiency. His post boil gravity will become his brewhouse efficiency.

Just had a thought guitarguy, what is the gravity of your final runnings? If it is over 1.008 then slowing down your sparge or moving to a different sparge method may increase your lauter efficiency.

 

[SpeedYellow]

Efficiency problems are unlikely to be caused by mash temps (unless your thermometer is way off) or pH, so you're probably barking up the wrong tree. But to answer your question, you DO need to calibrate your brewing thermometer. Better yet, just use a glass lab thermometer for the mash; not only are they accurate, but they also have a slow response time which is great for the mash because it gives you an average (and no matter how well you stir, the mash temps are never very uniform so digital is hard to use).

 

[guitarguy6]

Efficiency problems are unlikely to be caused by mash temps (unless your thermometer is way off) or pH, so you're probably barking up the wrong tree. But to answer your question, you DO need to calibrate your brewing thermometer. Better yet, just use a glass lab thermometer for the mash; not only are they accurate, but they also have a slow response time which is great for the mash because it gives you an average (and no matter how well you stir, the mash temps are never very uniform so digital is hard to use).

Ya I'm going to make sure my equipment is properly calibrated and use a glass thermometer I purchased from my LHBS. I'm also going to try a small 2-3Gallon BIAB and see what sort of efficiency I get.

 

[jfr1111]

Ya I'm going to make sure my equipment is properly calibrated and use a glass thermometer I purchased from my LHBS. I'm also going to try a small 2-3Gallon BIAB and see what sort of efficiency I get.

I would try using the same process or only changing one variable at a time to insure you find the source of your problem. Decreasing batch size and going to BIAB might make an increase (or decrease) in efficiency, but you will not know precisely why. Calibrate your new thermometer and brew a new batch using the same process as before. Use a little more grain and plan for lower efficiency if you want the recipe to still turn out as intended or compensate with DME at the end of the boil.

Incorrect volume measurements can also impact efficiency (ie. using too much strike water and /or sparge water compared to what the recipe calls for). This is easy to check for and I'd check for it, both pre-boil and post-boil.

 

[guitarguy6]

I just started a quick 3 gallon biab after calibrating my equipment and so far it's going well. The grains have been mashing for 30min while I give the grains a stir every 10min and my brix reading is 12 which is slightly higher than what brewtarget estimated my pre-boil gravity to be using %70 efficiency. I'm thinking my problem was a mix of wrong mash temperature and not stirring the grain at all during mash.

 

[guitarguy6]

I just started a quick 3 gallon biab after calibrating my equipment and so far it's going well. The grains have been mashing for 30min while I give the grains a stir every 10min and my brix reading is 12 which is slightly higher than what brewtarget estimated my pre-boil gravity to be using %70 efficiency. I'm thinking my problem was a mix of wrong mash temperature and not stirring the grain at all during mash.

Is this a goood brix to SG calculator? http://www.brewersfriend.com/brix-converter/

 

[guitarguy6]

After 2 consecutive successful 3 gallon BIAB on my home stove I brewed a full 5 gallon batch today using my mash tun, hlt and 19 gallon kettle with a blichmann 4500Watt boil coil. I stirred my mash tun every 15min for an hour at 152F and used a glass thermometer as well as a fairly cheap thermapen to monitor temps. Instead of fly sparging I did a 2 step batch sparge. Drained mash tun, added water, stirred, waited 10 min and drained both times. Using this method I had about %85 efficiency. I had to add water after the boil as I originally estimated %75 efficiency. Was going for an APA but would've ended up with an ABV of just over %8. My next brewday I will go back to fly sparging but stir the grains during the mash and also a few times during the fly sparge.