Beginner Tip: Efficiency/Doughing-in

[Sweetwort-Hopkins]

Good morning, HBT'ers.

I've been brewing for just over 1yr. Started with all-grain right off the bat. I use a 10gal Igloo as a mash-tun - initially fitted with a sink hose but recently upgraded to a false bottom ($44- at my LHBS, well worth it! I saw an increase from 69% to 79% efficiency).

I use Brewersfriend.com pretty much exclusively for calculations, including the strike water calculator. Here's where one of my processes had previously been sketchy; I would always pre-heat the Mash Tun by adding strike water a few degrees higher than the calculator suggested (I think I saw something about pre-heating the MLT on Youtube or something and it sounded like a great idea). In doing this, I would then wait for the strike water to drop to the suggested dough-in temp but 95% of the time my mash would end up being 4 or 5 degrees higher than my target rest temp. Zoinks!! Now, no matter how much stirring, my grain would effectively be converting at a higher than desirable temp for a solid 10-15mins. When the mash finally hit the desired temp, I would seal the tun and set a timer for about 45-50mins considering the amount of time the grains sat at a too-high temp.

My OG would always be a handful of points lower than what I was aiming for and I kinda just 'blamed' it on the Igloo MLT. The majority of my beers would finish drinkable and I was even highly impressed by a few batches - hate to mention that I dumped two batches along the way due to uncontrolled fermentation temps -- that was remedied quickly by building a fermentation chamber.

Now, here is what I'm really getting at: pre-heating the MLT does not jive with the strike water calculators!!!

The calculator assumes that you will add the strike water at the suggested temp and then dough-in immediately.

For my last few batches, I did just that. Woohoo! No more stirring like a mad man. No more crappy conversion. No more gravity woes.

I have been able to seal the tun and set my timer pretty much instantly after doughing-in the grains. I have had the temp land exactly at my target twice, and that's immediately after putting down the mash paddle. I only lose about one degree F during the rest. My OG has been spot-on three times in a row. All of these improvements I am damn sure result from NOT pre-heating the MLT.

Just figured I'd share since I've learned so much from HBT in the past year or so.

Happy Brewing!!

 

[mrgrimm101]

Great to know. I am moving to all grain very soon and this is helpful information. Thanks!

 

[k1ngl1ves]

The more you learn about your equipment, the better you can control your temps.

 

[donk5]

What does the mash temp have to do with efficiency? Mash temp should only influence FG as it determines amount of fermentable sugars not amount of all sugars.

 

[Sweetwort-Hopkins]

What does the mash temp have to do with efficiency? Mash temp should only influence FG as it determines amount of fermentable sugars not amount of all sugars.

Well, I guess I'm equating more like an overall efficiency. Ie; hitting temps, hitting gravities more accurately without as much room for error.

I don't disagree with you. It is quite possible that my efficiency (mash) rose when I switched to a false bottom.

I'll edit out the efficiency stuff in the original post as to not confuse anyone. Thanks for the heads-up!

 

[carvetop]

Regarding a mash tun pre-heat which becomes very important this time of year (at least in my area and for my garage brewery setup), I've found that adding a few quarts of boiling water to the mash tun while the strike water heats up is sufficient. Once the strike water is ready, I dump the water from the mash tun and add the strike water.

 

[MagicMatt]

I would always pre-heat the Mash Tun by adding strike water a few degrees higher than the calculator suggested ...

I think you misunderstood what "preheating the MLT" means. Every encounter I've seen where people do this (I do not), they add about a gallon or so of boiling water to the MLT and close it up for about 5-10 minutes, then dump it. This preheats the MLT so that it's at closer to mash temps than ambient temps, and thus you should lose less heat when adding your strike water.

You're always going to lose a bit from the grain at a minimum, and likely some to the MLT too. Preheating is to lessen the effects of heat loss due to the MLT being room temp to begin with. If you know your equipment well enough to avoid preheating and can produce consistent results, there is no need to preheat.

For me, with a 10 gal Igloo cooler and false bottom, my strike temp depends on what time of year (read: ambient temp) it is. During the spring, summer, and fall, I heat my strike volume to 10°F warmer than my target mash temp. During winter, it's 12°F. In my experience, it takes at least 10 minutes for the temperature to stabilize, so I'm kind of questioning how you hit your mash temp as soon as you dough in. It's not really thermodynamically possible.

 

[thekraken]

I think you misunderstood what "preheating the MLT" means. Every encounter I've seen where people do this (I do not), they add about a gallon or so of boiling water to the MLT and close it up for about 5-10 minutes, then dump it.

For the record I preheated my tun the way that OP did, and I've seen the procedure he describes mentioned many a time here on HBT. Seems like the least wasteful way to do it anyway. Also, I wouldn't throw boiling water into a plastic tun.

Another for the record: Even when I used to preheat my tun I still struggled to hit my mash temps (usually missed too low). I don't think it's so much that the calculators don't jive with preheating the MLT but that everyone's equipment is different. It's a matter of developing that skill as a brewer to know how to nail your temps on your equipment. That's great that you figured it out for your system, OP. ...I just got mad, gave up, and built a RIMS tube.

 

[MagicMatt]

For the record I preheated my tun the way that OP did, and I've seen the procedure he describes mentioned many a time here on HBT. Seems like the least wasteful way to do it anyway.

I hear ya, but I still disagree. "Strike temp" is to account for heat loss due to MLT and grain temps. This is why the strike temp is always greater than mash temps.

A preheat is a separate step, with separate water. Most people do not do this separate step, however everyone adjusts their strike temp (even with a preheated MLT, you'll still need to account for heat loss due to grain absorption).

Otherwise, if you're just heating your strike water hotter, that doesn't change anything regarding your process - it's still the strike temp.


I guess if you overheat your strike water and then let it sit in the MLT for a while before doughing in then technically you preheated with strike water, but to me that's a mixing of terminology.

 

[Gavin C]

In beersmith (don't know about brewers friend) you enter a few variables to get the right strike temp.

1. Mash tun weight
2. Mash tun material
3. Mast tun temperature
4. Grain temperature
5. Grain weight, Water volumes too of course.

If you fill the mash tun with strike water warmer than the planned strike temp and allow it to come down to strike temp you can assume MT temp to be identical to strike temperature and enter it as such.

That leasves you only with the variables

1. Mash tun weight
2. Mash-tun material
3. Grain weight and its temperature
4. Strike water volume

 

[pricelessbrewing]

In beersmith (don't know about brewers friend) you enter a few variables to get the right strike temp.

1. Mash tun weight
2. Mash tun material
3. Mast tun temperature
4. Grain temperature
5. Grain weight, Water volumes too of course.

If you fill the mash tun with strike water warmer than the planned strike temp and allow it to come down to strike temp you can assume MT temp to be identical to strike temperature and enter it as such.

That leasves you only with the variables

1. Mash tun weight
2. Mash-tun material
3. Grain weight and its temperature
4. Strike water volume

This, I also haven't used BF too much apart from like a year ago when I looked at it (found it clunky and cumbersome, way too many different pages to go through) before launch my own water volumes and temps calculator.

As gavin frequently says, GIGO. If you enter the wrong variables, or ignore some of them, then you're going to end up with inaccurate info. FWIW, my calculator ASSUMES the mash tun is at heated to the same temp as the strike water. This means that the strike water is 100% accurate for BIABers, and for mash tun brewers you need to preheat your mash tun or determine the additional few degrees that are needed to compensate.

 

[thekraken]

I hear ya, but I still disagree. "Strike temp" is to account for heat loss due to MLT and grain temps. This is why the strike temp is always greater than mash temps.

A preheat is a separate step, with separate water. Most people do not do this separate step, however everyone adjusts their strike temp (even with a preheated MLT, you'll still need to account for heat loss due to grain absorption).

Otherwise, if you're just heating your strike water hotter, that doesn't change anything regarding your process - it's still the strike temp.

I guess if you overheat your strike water and then let it sit in the MLT for a while before doughing in then technically you preheated with strike water, but to me that's a mixing of terminology.

I don't think we're mixing terminology, I think it's just a different way of skinning the cat that you haven't stumbled across yet.

 

[Sweetwort-Hopkins]

I hear ya, but I still disagree. "Strike temp" is to account for heat loss due to MLT and grain temps. This is why the strike temp is always greater than mash temps.

A preheat is a separate step, with separate water. Most people do not do this separate step, however everyone adjusts their strike temp (even with a preheated MLT, you'll still need to account for heat loss due to grain absorption).

Otherwise, if you're just heating your strike water hotter, that doesn't change anything regarding your process - it's still the strike temp.


I guess if you overheat your strike water and then let it sit in the MLT for a while before doughing in then technically you preheated with strike water, but to me that's a mixing of terminology.

Right right. I mentioned that I pretty much exclusively use Brewersfriend for calculations. With that calculator, I've done both pre-heating with 1/2gal of boiling water and then dumped, and also thrown the entire strike volume in at a slightly higher temp - neither approach worked for me. I would always end up with a few degrees too high once my grain was in the tun.

Everyone's brew gear is different. My intention is to share what seems to have been a 'nail in the coffin' process for hitting your target mash temp without going bananas (like I have) after doughing-in. It may not work for everyone. But, given my equipment and experience, this info would've been Gold for my first dozen batches. My Igloo holds super thoughout a 60min rest. There may be coolers that drop a few degrees during the rest - in that case, maybe pre-heating is necessary.
Cheers

 

[Sweetwort-Hopkins]

When you're brewing a DIPA and shooting for a 149F rest to maximize fermentable sugars but landing at 156F after doughing-in... Panic ensues.

As I mentioned, this is like the first major component of brewday - The Mash.

I have a thread on here somewhere where I asked about missing rest temps after doughing-in. All replies were constructive. We hate to add ice or cold water when temp is too high and bringing the temp of 18lbs of grain and 6gals of water up (if you undershoot) can be a crapshoot as well.

 

[WinterFitz]

Hey read through the posts and had a question y'all might be able to help me with, I've been stuck in an efficiency between 60%-65% (closer to 60) since I started all grain.

I batch sparge, letting the first sparge sit for about 15 minutes and the second sit for about 10 minutes before lautering. I stir the grains with each sparge. Generally I end up taking more wort than I need to cover boil off and boil down to get to where I need to be pre-hopping.

I've checked the gravity of the wort still in the mash tun after and I'm getting readings of 1.020 ish.... Not always but always above 1.010. So I know I'm leaving sugars behind and so my efficiency is definitely sucking because of that.

Is there a good way to correct for this or am I better off to just continue to sparge until it gets down to 1.010 and then boil off until I get to my preboil volume?

My first thought was to double crush at the LHBS but since I am seeing the sugars I'm not sure if that would help or not

Thanks!!!
Paul

 

[gromitdj]

Hey read through the posts and had a question y'all might be able to help me with, I've been stuck in an efficiency between 60%-65% (closer to 60) since I started all grain.,,

Your crush could be the culprit. I use a similar mash procedure as you and routinely get 85%. However, I crush my own grains.

Also, what kind of false bottom are you using? You could be "channeling" the sparge and not rinsing the grains thoroughly. But a Batch Sparge typically remedies this to a certain degree.

I have never tested my remaining wort post sparge, so I'm not sure how much I am leaving behind.

 

[doug293cz]

Hey read through the posts and had a question y'all might be able to help me with, I've been stuck in an efficiency between 60%-65% (closer to 60) since I started all grain.

I batch sparge, letting the first sparge sit for about 15 minutes and the second sit for about 10 minutes before lautering. I stir the grains with each sparge. Generally I end up taking more wort than I need to cover boil off and boil down to get to where I need to be pre-hopping.

I've checked the gravity of the wort still in the mash tun after and I'm getting readings of 1.020 ish.... Not always but always above 1.010. So I know I'm leaving sugars behind and so my efficiency is definitely sucking because of that.

Is there a good way to correct for this or am I better off to just continue to sparge until it gets down to 1.010 and then boil off until I get to my preboil volume?

My first thought was to double crush at the LHBS but since I am seeing the sugars I'm not sure if that would help or not

Thanks!!!
Paul

A SG of 1.020 in the final retained wort is typical when batch sparging. So, I don't see a problem there.

Can you provide some numbers:

• Total grain wt
• Strike water volume
• First runnings volume
• First runnings SG
• Sparge water volume for each sparge

You should be getting mash efficiencies in excess of 75% with batch sparge and good (near complete) starch conversion. Your problem is most likely incomplete starch conversion. Finer crush and/or longer mash times should help with conversion.

Channeling is a total non-issue for batch sparge.

Brew on

 

[WinterFitz]

Hey guys thanks for the quick response!

Gromit, my mash tun is a rectangular picnic cooler, and I'm using 3 separate steel braids, leading into a common manifold. They are laid out evenly throughout the bottom of the cooler.

Doug,
I'm currently traveling on business right now so I don't have my complete notes with me. However,

Grains were 8.05 lbs
Mash was 3 gals to start and halfway through added an addition 2lts of boiling water to bring temp back up it had dropped about 3 degrees if I remember correctly. I've been keeping my temperature at 155F and it'll drop to about 151 unaided over the course of 60 minutes. I have not been using an iodine test to check for starch conversion.

Each sparge was with 2 gals of water @ 170.

I don't have a figure for my first runnings but I collected a total of 5 gal of wort which I boiled down to 4.1 gals to begin my boil.

Sorry I forgot to mention this was a 3 gal batch.

Thanks,
Paul

 

[doug293cz]

Hey guys thanks for the quick response!

Gromit, my mash tun is a rectangular picnic cooler, and I'm using 3 separate steel braids, leading into a common manifold. They are laid out evenly throughout the bottom of the cooler.

Doug,
I'm currently traveling on business right now so I don't have my complete notes with me. However,

Grains were 8.05 lbs
Mash was 3 gals to start and halfway through added an addition 2lts of boiling water to bring temp back up it had dropped about 3 degrees if I remember correctly. I've been keeping my temperature at 155F and it'll drop to about 151 unaided over the course of 60 minutes. I have not been using an iodine test to check for starch conversion.

Each sparge was with 2 gals of water @ 170.

I don't have a figure for my first runnings but I collected a total of 5 gal of wort which I boiled down to 4.1 gals to begin my boil.

Sorry I forgot to mention this was a 3 gal batch.

Thanks,
Paul

Ok, those numbers are enough to work with to get some idea of how your process is performing.

You used 3 + 0.5 + 2 + 2 = 7.5 gal of water total. Typical grain absorption for a traditional MLT is about 0.125 gal/lb, so the grain should have held on to 0.125 gal/lb * 8.05 lb = 1.01 gal. You collected 5 gal of wort, so there is

7.5 - (5 + 1.01) = 1.49 gal​

of water unaccounted for. The most likely cause of this is a high undrainable (dead) volume in your mash tun. This amount of MLT dead volume is excessively high, and adversely affects your lauter efficiency. Good MLT drain designs will only have 0.125 - 0.25 gal of dead volume. If you reduced your MLT dead volume to 0.125 gal, your lauter efficiency would go from about 74% to about 89% (assuming you still did two sparges and collected 5 gal pre-boil) !!! That's a huge difference.

Using your volumes and grain bill, I adjusted the starch to sugar conversion efficiency in the simulator to achieve a 62% mash efficiency. The conversion efficiency came out at 83.6% This is not terrible, but it is a long way from great. Homebrewers can achieve 95% or better conversion efficiency with optimized mash parameters. Usually the biggest detractor from conversion efficiency is mash time too short for the crush size used (coarser crushes take longer to convert due to diffusion rate effects.) Conversion efficiency can be improved by crushing finer and/or mashing longer.

Even with the 83% - 84% conversion efficiency, if your dead volume were reduced to 0.125 gal, the mash efficiency would be 74% - 75%. Increasing conversion efficiency to 95% would lead to about 84% mash efficiency.

Finally, with your original efficiencies, the simulator predicts a final sparge run-off SG of 1.0215.

Brew on