Mash Temperature Inconsistencies and Efficiency Issues

[Physics202]

I have a 15gal kettle with a steam pot insert (here) and am using a wilserbrewer fine mesh bag. We are brewing 10gal batches and just did our second fully all grain recipe. This last recipe called for 32 lbs of grain which we have come to realize is exceeding our limit for our current setup. Our first all grain recipe had 26lbs of grain and it seemed a little more manageable. We measured about 65% efficiency with our first AG batch, and a meek 52% efficiency with our second AG batch. One thing we have struggled a little bit with is acurately getting the desired mash temp from the calculated strike temp. I use a calculator, but I only estimate the grain temp and do not actually measure it. After we reach strike temp, we dough in, give the mash a solid stir and both times we have noticed the temperature is low. So, we then turn on the burner stir vigorously again until we reach the desired mash temp.

We cover the kettle with a winter coat and check the mash temp midway through the soak. Once I dial in our process, we'll omit this step. I've noticed that the mash is often a higher temp when I check midway through than when the mash starts. I'm noticing that the water temperature inbetween the kettle and the steam basket is heat up quite a bit, but despite vigorous stirring, it will not transfer into the mash itself. I noticed this more so with the recent overload batch of 32lbs of grain. Is there anyone else struggling with getting mash temps from strike water temps, and also anyone else have issues with the mash absorbing the water temp when heating up.

I'm realizing that the volume of water that the mash sits in is actually different than the volume of water in the pot, and the thermal capacity in the extra water in the pot doesn't transfer through the mesh bag and mash in a desirable way.

 

[pricelessbrewing]

What calculator are you using.

Please provide recipe and all measurements you took. Looks like you're doing no sparge?

If you want to calculate efficiency, you need three things. Without at least gravity and volume, then you're calculation is worthless, without temperature then your calculation is a little inaccurate (+- 4%)

1) Gravity reading, let the sample cool to room temp, and stir the wort thoroughly before taking a sample.

2) Volume measurement. The more accurate the better, I recommend using a stainless ruler, or a carefully made dip stick to the nearest half liter.

3) Temperature reading: Wort/water expands as it is heated, and so you need to account for this when measuring the volume.

Please reply with full recipe and instructions (expected and measured volumes and gravities at each step)

I recommend measuring at least three points to fully understand your brewday, first runnings (gives conversion efficiency and absorption rate), pre boil (gives lauter, and mash efficiency), and postboil (gives boil off rate).

 

[wilserbrewer]

Try a batch without the basket, more room for grain and easier to heat the mash. STIR constantly if you need to add a little heat, but with an accurate strike temp you shouldn't need to add any heat during the mash.

Sometimes I feel a basket can be more of a hindrance than help. JMO

As you are learning, a 20 gal kettle is better sized for 10 gal batches.

 

[doug293cz]

Try a batch without the basket, more room for grain and easier to heat the mash. STIR constantly if you need to add a little heat, but with an accurate strike temp you shouldn't need to add any heat during the mash.

Sometimes I feel a basket can be more of a hindrance than help. JMO

As you are learning, a 20 gal kettle is better sized for 10 gal batches.

I gave up using the basket after a few brews for the same issues that OP is experiencing. If you aren't doing a recirculating mash, then don't use the basket.

Brew on

 

[Physics202]

What calculator are you using.

Please provide recipe and all measurements you took. Looks like you're doing no sparge?

We rinse the grains with some hot tap water as they hang over the boil kettle.

If you want to calculate efficiency, you need three things. Without at least gravity and volume, then you're calculation is worthless, without temperature then your calculation is a little inaccurate (+- 4%)

We took our gravity reading after we cooled the wort down to ~70degrees and got 1.060. We do not have volume markings on our boil kettle, but used volume markings on my fermentation buckets. We ended up with 11gallons.

1) Gravity reading, let the sample cool to room temp, and stir the wort thoroughly before taking a sample.

2) Volume measurement. The more accurate the better, I recommend using a stainless ruler, or a carefully made dip stick to the nearest half liter.

3) Temperature reading: Wort/water expands as it is heated, and so you need to account for this when measuring the volume.

Please reply with full recipe and instructions (expected and measured volumes and gravities at each step)

I recommend measuring at least three points to fully understand your brewday, first runnings (gives conversion efficiency and absorption rate), pre boil (gives lauter, and mash efficiency), and postboil (gives boil off rate).

Here's my notes/recipe from brew day:
Recipe Type: All Grain
Yeast: Wyeast 3711
Yeast Starter: Yes
Batch Size (Gallons): 11
Original Gravity: 1.060/1.064@65%
Efficiency: 52%????
Final Gravity:
IBU: 24
Boiling Time (Minutes): 60
Primary Fermentation (# of Days & Temp): ____________ days at 70 degrees
Secondary Fermentation (# of Days & Temp): None

26# Belgian Pilsner
6# Rye
2lb D90 Candi Syrup

Mash for 60 minutes at 152 degrees.

2oz Brewer’s Gold @ 60
6oz saaz @ 10
2lb D90 Candi Syrup @10

The second reading under gravity was my expected gravity according to brewer's friend with 65% efficiency.

We mashed in with 11.5gal. Sparged till we were at approx 13gal. Ended up with 9gals after the boil... (still figuring out my new burner), and we topped up with 2gals to make the end result of 11gal.

We only did the one gravity measurement at the end after the wort was cooled and 2gal water added.

 

[Physics202]

Try a batch without the basket, more room for grain and easier to heat the mash. STIR constantly if you need to add a little heat, but with an accurate strike temp you shouldn't need to add any heat during the mash.

Sometimes I feel a basket can be more of a hindrance than help. JMO

As you are learning, a 20 gal kettle is better sized for 10 gal batches.

My only concern is removing the bag. It's heavy as crap and we don't have a pulley. I also quite liked the idea of having a gap between the bottom of the kettle and the grain in case I had to further heat the mash, but I'm realizing this might actually be a hindrance. I'll probably try no basket if I get a pulley. I'm realizing our kettle is a bit small for 10gal batches. I think we're going to max our grain around 28lbs and use extract to compensate for higher gravity beers.

 

[wilserbrewer]

Yes agreed, when you start getting up to 20-30 lb plus grain bills, a ratchet pulley is highly recommended.

I've done 30 plus both with and without a pulley, night and day.

 

[wilserbrewer]

I also quite liked the idea of having a gap between the bottom of the kettle and the grain in case I had to further heat the mash, but I'm realizing this might actually be a hindrance.

If you continue with a basket and are trying to heat the mash, I would suggest draining out some of the heated wort below the basket into a pitcher and pouring it back into the top of the kettle to distribute the heat to the mash, a manual recirc of sorts.

If you do not have a valve on your kettle, simply raising the basket up and down several times allowing it to partially drain will help mix the heated wort outside the basket with the mash.

 

[newnick]

So this is like doing a 5.5 gal. batch in a 7.5 gal. kettle, with a basket?
Might want to try doing something like a 7.5 or 8 gal. batch with the full volume of water to get dialed in on your system.
I've got your kettle's baby brother and although I recirculate now, I did a lot of batches without recirculating and I don't believe the basket causes any issues.

 

[newnick]

One more thing, get your grain crushed finer. It will help your numbers out the way your mashing.

 

[IslandLizard]

Yeah, +1^ on the finer grain crush to increase efficiency. Makes a larger difference than anything else!

Most, if not all brew stores crush quite coarsely (wide gap). Realize that even running through twice on a wide gap is not better than once on a narrower gap. This is especially true for rye and wheat kernels as they are smaller, and most will pass through uncrushed if the gap is too wide. 0.020-0.022" for small kernels, like Rye, Wheat, flaked adjuncts etc. and 0.026-0.028" for Barley works great for me. I don't BIAB, just using a converted cooler. Since you use a bag (BIAB) you can crush very fine and lautering will never get stuck.

A good sparge eeks out more high gravity wort, so after lifting and draining, dunk that bag into a large bucket with warm or hot water (<168F), stir, then drain again. It will add several points to your wort.

Agreed that a 15 gallon kettle is a bit small for 10 gallon batches especially when you do BIAB, since the mashing grains take up a significant volume too.

Most of my brews are 5.5-6 gallon in an 8 gallon kettle, and it's a bit tight. Same with my 15 gallon kettle for 11-12 gallon brews. But it works if you're careful. I sometimes hold back a gallon of the 3rd runnings and add it after I've boiled off some. To compare, keggles are 15.5 gallons and look at how many of us use those for 10-11 gallon brews.

Now 10 and 20 gallon kettles respectively give you a lot of extra room, a luxury that almost asks for more wort...

 

[RM-MN]

1. Get rid of the basket. It takes up room in the pot so your grains are more constrained. You need all the water to have access to the grains, not some of it outside the basket where is just sits. Get your strike water temp calculates so you don't have to add heat and you don't need the basket anyway.
2. Crush finer, then reduce the amount of base malt. You can plan on higher efficiency with the finer crush so you don't need as much base malt and perhaps less of the other grains as well as you will be able to get more color and flavor extracted with the finer crush.
3. Once you have your correct strike temp, stir in the grains really well and put the lid on your pot. Insulate it and don't do anything to it for the mash period. If you open it to take a temp reading, you lose heat. If you add heat, you destroy part of the enzymes that you depend on to convert the starches. You can chase the temperature all day without ever improving the conversion. Milled fine, your grains will be converted before the mash temperature goes down a single degree.
4. Use a tape measure and calculate the volume of water or wort in the pot. Mark the pot where your strike water should come to so you always get the same amount. It will make calculating the strike temp more accurate. You need a good themometer for all grain so use it for everything, including the temperature of the grain. Weigh the grain too and plug the numbers into your strike temp calculator to get an accurate strike temp.
5. Use less than full volume of water for you mash, reserving a little for a sparge. It doesn't take a lot to increase the amount of sugar you can recover. Hot water means you get to the boil temp sooner but cold water works fine for sparging. Pour over works about as good as a dunk sparge and leaves you with one less vessel to clean.

 

[Physics202]

Unfortunately I don't have a valve on my kettle. I'll try lifting the gran out and submerging it strategy. Since having this issue, I've realized a way to recirculate would be nice. Have also been looking at electric heat recirculating setups. I'm only 6 brews in, but maybe I'll start saving towards a bigger better system. Going to be building a house later this year, so I have the potential to have a nice garage setup with wiring and plumbing and the sort.

This last brew was also the first time that I crushed my own grain. I researched settings a little bit, but ended up going with the factory setting of .029. I'll shrink it down a bit for next brew. I still have lots of experimenting and learning to do with my process.

Thanks everyone for responses. I think next brew will go a little better.

 

[RM-MN]

Unfortunately I don't have a valve on my kettle. I'll try lifting the gran out and submerging it strategy. Since having this issue, I've realized a way to recirculate would be nice. Have also been looking at electric heat recirculating setups. I'm only 6 brews in, but maybe I'll start saving towards a bigger better system. Going to be building a house later this year, so I have the potential to have a nice garage setup with wiring and plumbing and the sort.

This last brew was also the first time that I crushed my own grain. I researched settings a little bit, but ended up going with the factory setting of .029. I'll shrink it down a bit for next brew. I still have lots of experimenting and learning to do with my process.

Thanks everyone for responses. I think next brew will go a little better.

Recirculating systems with temperature control may seem like a good strategy, in practice they cause as many problems as they solve. I've experimented with shorter mash periods using iodine for an indicator of the conversion from starch to sugar and with very fine milling I've found that the conversion takes as little as 3 minutes. If your conversion is done that quickly, how much will it help to recirculate? Instead of spending a large amount of money on the recirculating system, spend a few minutes making the conditions right for fast conversion so you don't have to worry about falling temperatures.

Note that I said that conversion is quick. Extracting flavors seems to take longer and when I tried doing the short mash I got great conversion but the resulting beer lacked flavor. I now recommend at least a 30 minute mash to ensure conversion and extraction of flavors.

 

[wilserbrewer]

Recirculating systems with temperature control may seem like a good strategy, in practice they cause as many problems as they solve.

Well put, I like this... The way I figure the enzymes are inside the kettle, and can't see the PID display to let them know they are at 152 or 153

 

[Physics202]

Recirculating systems with temperature control may seem like a good strategy, in practice they cause as many problems as they solve. I've experimented with shorter mash periods using iodine for an indicator of the conversion from starch to sugar and with very fine milling I've found that the conversion takes as little as 3 minutes. If your conversion is done that quickly, how much will it help to recirculate? Instead of spending a large amount of money on the recirculating system, spend a few minutes making the conditions right for fast conversion so you don't have to worry about falling temperatures.

Note that I said that conversion is quick. Extracting flavors seems to take longer and when I tried doing the short mash I got great conversion but the resulting beer lacked flavor. I now recommend at least a 30 minute mash to ensure conversion and extraction of flavors.

What sort of mill setting are you talking about? I'm definetly going to experiment with mill settings, but the advice my LHBS told me was that the goal of grain crushing was to just crack the husks and not grind the grain itself. He explained that having ground grain can relaese tannins which add bitterness to the beer. I haven't had time to research the validity of this.

 

[pricelessbrewing]

Common statement from older brewers that aren't active online.

Tannin extraction is a function of ph mostly, and temp to a lesser degree. Grain crush is completely irrelevant.

 

[wilserbrewer]

but the advice my LHBS told me was that the goal of grain crushing was to just crack the husks and not grind the grain itself.

IMO this is horrible advice and could be a fatal flaw in successful brewing at any level.. See below links on crushing whereby the author states that many homebrewers undercrush. You certainly want to do a lot more than merely "crack the husks". I also found it very interesting that the "expert" did not set the mill to a specified thousands gap, but just closely inspected the grist. Use your eyes, that's what they are there for

I think many home brewers use a coarse mill setting simply because that's how their mills were set at the factory, and also because they don't know what a normal crush is. The manufacturers, in turn, err on the side of caution because they do not want to be blamed for lautering problems. The same, I believe, is true of many home brew shops who mill grain for their customers. "
"


article
http://brewlikeapro.net/maltmilling.html

pic
http://brewlikeapro.net/images/milled_grain.jpg

 

[RM-MN]

What sort of mill setting are you talking about? I'm definetly going to experiment with mill settings, but the advice my LHBS told me was that the goal of grain crushing was to just crack the husks and not grind the grain itself. He explained that having ground grain can relaese tannins which add bitterness to the beer. I haven't had time to research the validity of this.

I use a Corona style mill and I can't set it any closer because the plates that do the grinding are already rubbing. Any tighter and I can't turn the crank.

The idea that you shouldn't mill the grains fine has been debunked but it will take forever to inform some people. Unless your pH rises to over 6.0 you can't extract tannins, not from milling fine, not from squeezing the bag of grains. You can even boil your grain without extracting tannins if you keep the pH where it should be.

 

[Physics202]

Had another brew and made some improvements.

First, I got ahold of some feeler guages and adjusted my mill to .025 (it was at .039 last time...). To me, this visually looked like it really ground up the grain pretty good, but maybe overly ground??? Maybe I'll get a pic next time.

Second, we previously had too much grain (32lbs) for my current 15gal pot w/ steam pot insert. This recipe only called for 27lbs, and we mixed this with 11gallons of water. This was more manageable and seemed like a better consistency mash. This puts us at a 1.63qt/lbs ratio, which I've read should be good. Although the mash itself is sitting in less water due to the confinement of the steam basket.

Third, we mashed for 90minutes. Not really because we felt we needed to, but we were busy bottling a previous brew and just decided to let it sit until we were at a good stopping point. Mash temps only varied 2 degrees during this time.

We ended up getting 69% efficiency, which is our best to date, but still quite a bit lower than desired. I did not measure my mash PH, and I don't have a water report (well water). I have a nice PH meter that I use for hot sauce making, and our local HBC does water testing, so I think my next step is to take advantage of those.

 

[RM-MN]

Had another brew and made some improvements.

First, I got ahold of some feeler guages and adjusted my mill to .025 (it was at .039 last time...). To me, this visually looked like it really ground up the grain pretty good, but maybe overly ground??? Maybe I'll get a pic next time.

Second, we previously had too much grain (32lbs) for my current 15gal pot w/ steam pot insert. This recipe only called for 27lbs, and we mixed this with 11gallons of water. This was more manageable and seemed like a better consistency mash. This puts us at a 1.63qt/lbs ratio, which I've read should be good. Although the mash itself is sitting in less water due to the confinement of the steam basket.

Third, we mashed for 90minutes. Not really because we felt we needed to, but we were busy bottling a previous brew and just decided to let it sit until we were at a good stopping point. Mash temps only varied 2 degrees during this time.

We ended up getting 69% efficiency, which is our best to date, but still quite a bit lower than desired. I did not measure my mash PH, and I don't have a water report (well water). I have a nice PH meter that I use for hot sauce making, and our local HBC does water testing, so I think my next step is to take advantage of those.

I don't think you can overly grind the grain with a roller mill when you are doing your mash in a bag. Some people here even put their grain in the blender to get it finer.

Try a batch without the steam basket. With a .025" mill gap and a 90 minute mash I think you should have been getting upwards of 80% efficiency.

 

[pricelessbrewing]

I'll say it again, if you're troubleshooting your mash /crush then you should use your conversion efficiency.

 

[Physics202]

I don't think you can overly grind the grain with a roller mill when you are doing your mash in a bag. Some people here even put their grain in the blender to get it finer.

Try a batch without the steam basket. With a .025" mill gap and a 90 minute mash I think you should have been getting upwards of 80% efficiency.

Unfortunately I don't have a feasible way to rig a pully at the moment and can't lift the grain bag and sparge and squeeze without the steam basket. I think with this most recent mash concentration, the water infiltrated the mash sufficiently. For now I have to live with the steam basket, although I do eventually plan to rig a pully and perhaps experiment without the steam basket.

I'll say it again, if you're troubleshooting your mash /crush then you should use your conversion efficiency.

At this early stage of my brewing experience, I have a lot of experimentation that I want to do to make things more efficient. My first major concern was the mash/crush and we'll probably try some other crush settings to see how they compare. The other concern is the Mash PH, which I'll also be monitoring here soon. Just bought some 4 and 7 buffer to properly calibrate my PH monitoring device.

 

[pricelessbrewing]

Good luck. Do you have a refractometer? If so, taking specific gravity samples throughout the mash is a great way to determine how well the mash is converting. I usually get full conversion in 40-45 minutes with a good crush and a 1.75 qt/lb or greater mash thickness.