Author Topic: When is thin too thin?  (Read 773 times)

Offline Stevie

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When is thin too thin?
« on: November 29, 2015, 09:22:57 PM »
Question for those BIABers out there that mash full volume. At what point do you consider withholding some water from the mash? 4 qts/lb, 5 qts/lb? Just curious.

Offline dmtaylor

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Re: When is thin too thin?
« Reply #1 on: November 29, 2015, 10:29:22 PM »
"They" say don't go more than 3 qt/lb.  This ensures good enzymatic concentration for proper conversion and fermentability.
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Offline Stevie

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When is thin too thin?
« Reply #2 on: November 29, 2015, 10:57:11 PM »
That is what I have heard in the past, but recently I'm seeing more and more folks going against that and mashing full volume every time no matter the thickness. At 70% eff, most beers sub 1.058 would be at or above 3 qts/lb.

I get what you are saying about enzymes, but I was thinking pH control would be a bigger issue.

Edit - I understand that total volumes needed will vary greatly based on a systems size, losses, and evaporation. A 2.5 gallon batch could have a much thinner mash compared to a 5 or 10 gallon batch if evaporation stays fairly constant.
« Last Edit: November 29, 2015, 11:12:26 PM by Steve in TX »

Offline a10t2

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Re: When is thin too thin?
« Reply #3 on: November 30, 2015, 12:55:41 AM »
I've never done thinner than 4 qt/lb, but that's pretty routine and I get the expected efficiency.
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Offline Pricelessbrewing

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Re: When is thin too thin?
« Reply #4 on: November 30, 2015, 05:38:45 AM »
 For comparing mash thickness, I think conversion efficiency should be discussed, as variables such as grain absorption, "losses" at mash tun or kettle should have no baring in the discussion.

 For me, I find conversion efficiency to be highest with a fine grind, and a traditionally thin mash. I usually mash in around 1.75-2 qt/lb. This ensures a high conversion efficiency (typically 97%+) while still leaving me water to achieve a high lauter efficiency (80-85%) which gives me a high, consistently predictable mash efficiency around 85+% depending on grain bill and brewhouse efficiency depending on grain bill and hop bill.

All efficiency numbers calculated using braukaisers definitions, and simulations ran using my calculator below.
http://pricelessbrewing.github.io/BiabCalc/

Any discussion of efficiency is relative without super informative posts, and not stating which efficiency is being mentioned isn't all that helpful in my experience.

Offline Stevie

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Re: When is thin too thin?
« Reply #5 on: November 30, 2015, 06:05:39 AM »
I see what your saying about volume losses not playing a role, but evaporation certainly would.

The only efficiency I care about is mash (actual sugar/possible sugar). I know some call that lauter while mash efficiency accounts for losses to the tun.

The point of the question is to discuss when is a mash too thin with BIAB. I only noted efficiency to layout an example of how easy it is to go beyond 3 qt/lb. I batch sparge, so this is purely curiosity.

You mention mashing at more traditional ratio. Why did you settle on that amount? Have you tried closer to 4 qts/lb?

Offline Pricelessbrewing

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Re: When is thin too thin?
« Reply #6 on: November 30, 2015, 06:17:57 AM »
I did full, or nearly full, volume mashes for about 2.5 years for BIAB'ing.

Well the main reason I switched was due to equipment constraints, I moved and left behind my big pots. I was doing .75-1.5G batches in a 2G pot. Coincidentally I had a 1G slow cooker which lined up perfectly with 1.7-2 qt/lb. Compounding this is that I have .5G boil off rate with the 2G pot, so with such small batches I get a substantial amount of malliard reactions and a higher than usual total water to grain ratio which would a no sparge mash thickness around 3 qt/lb.

Then I did a crap ton of reading on efficiencies and put in place the batch sparge / mash analysis section of my brewing/biab calculator and learned that the thinner mashes tended to have higher conversion efficiency (first running gravity and strike volume, aka extract converted and in the first runnings + retained wort).

For lauter, I (and braukaiser) define it as the extract produced by the combined gravity and volume for first and second runnings. For zero mash tun loss, mash = conversion * lauter.

Since I get high conversion efficiency, and high lauter efficiency due to a well done batch sparge, I have no intention of mashing full volume again unless I'm feeling extra lazy. Combined this gives me a high mash efficiency that I doubt I would be able to obtain for full volume mashing.

I have a predictable model thanks to braukaisers findings on batch sparge simulations, and doug293cz from HBT creating a simulation spreadsheet for BIAB.

Offline Stevie

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Re: When is thin too thin?
« Reply #7 on: November 30, 2015, 06:26:45 AM »
Your calculators are pretty cool BTW. Adding depth for volume measurement is a nice touch.

Offline erockrph

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Re: When is thin too thin?
« Reply #8 on: December 02, 2015, 05:34:12 AM »
I was seeing a dropoff in efficiency at about 3.5 qt/lb with a 60 minute mash. I extended my mash up to 75 minutes and now I can go as thin as 4 qt/lb and still be in the same efficiency range as my other brews.
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