mash volume - how thin is too thin?

[mcbar]

Quick question on mash volume: I know that 1.25 quarts of water per pound of grain is something of a standard to ensure sufficient enzyme concentration in the mash. What is the upper limit on that ratio? As the title suggests, how thin is too thin?

(Apologies if this information is located elsewhere. My search turned up a lot of places where this fact was listed, but no information on its limits.)

 

[LLBeanJ]

As long as mash pH is maintained in the 5.0-5.6 range, water to grain ratio is not all that important. BIABers typically do a no-sparge mash, so water to grain ratio will often be in the area of 3+ qts/lb. Mash pH is going to be driven by the water chemistry and the grain bill.

 

[mcbar]

As long as mash pH is maintained in the 5.0-5.6 range, water to grain ratio is not all that important. BIABers typically do a no-sparge mash, so water to grain ratio will often be in the area of 3+ qts/lb. Mash pH is going to be driven by the water chemistry and the grain bill.

Thanks for the reply. Reading about BIAB was part of what prompted my question.

 

[hoffmeister]

With my limited experience (2 +\- years all grain), everything I've read seems to suggest that 2 qts/pound was the upper limit. I'm not too familiar with BIAB techniques, but if your mash gets too thin it becomes harder for the enzymes in the grain to do their job converting starches into sugars, which will consequently drive your efficiency down. Maybe someone with some more BIAB experience can weigh in?

 

[thaymond]

In my limited experience with BIAB (20 or so batches) I started with full volume mashes and had low efficiency (60s). I moved to 1.5 qts/lb. At 1.25, my mashes were thick oatmeal. At 1.5 it's a little more manageable. My efficiency went from 60 to 80. I also double crush and squeeze the bag.

I'll then sparge with the remaining water at mash Temps to get my pre boil volume. Then squeeze again. My last efficiency was in the 80s.

This works for me, but everyone has a different setup that gives different yields.

 

[BrewSRQ]

Definitely not an expert, but my BIAB results have been fairly consistent. I calculate the absorption of my grains, and use enough water to make a half gallon shy of my preboil volume. I heat the remaining half gallon to about 170 and rinse my grains. Average between 75 and 83% efficiency.

My thinnest mash was probably BM's centennial blonde at about 2.6qts/lb. Notes say my efficiency was 76.48%

 

[Wrinkletusk]

Are we talking mash efficiency, or efficiency into the fermenter?

My last BIAB batch hit 78% mash efficiency (Hot Water Extract potential of 1.061, and hit 1.048). 5L/kg or 2.37qts/lb with a 3 litre sparge at mashout temp and drip (no squeeze).

79% marris
10% 25L crystal
10% Munich
1% acidulated
9g Gypsum
5g Epsom
5g CaCl

EZ Water estimated ph5.4

 

[LLBeanJ]

Are we talking mash efficiency, or efficiency into the fermenter?

For me, these are one and the same, as I have no mash tun or kettle loss.

My typical process is to hold back 1.5 gals for sparge and mash with the remaining water, which normally puts me close to or above 3 qts/lb. That's for a 60 minute boil. For a 90 min boil, the water to grain ratio goes even higher. For most mashes, I sacch rest for 60 minutes, but will push it to 75 or even 90 for light body mashes (<150°F) to ensure full conversion. I've never done an iodine test. My default efficiency setting in Beersmith is 80% and I rarely fall short, though I often exceed it by a point or three. This past Sunday I brewed a 7.5 gal 1.074 brew and hit my numbers right on the money with a 60 minute sacch rest @ 156°.

Don't get hung up on water to grain ratio. Keep your pH where it should be and it won't matter. If you're having efficiency probs, it's not due to water to grain ratio (unless the thin mash is creating pH issues and you're not adding the required salts/acid to compensate, which still makes it a pH problem, not a water to grain ratio problem).

 

[Twang]

Take a look at BruKaiser's experiment results.

"Contrary to common believe no attenuation difference was seen between a thick mash (2.57 l/kg or 1.21 qt/lb) and a thin mash (5 l/kg or 2.37 qt/lb)."

"A significant difference was however found in the efficiency. The brewhouse efficiency of the tick mashes remained almost constant between 58 and 60% over the temperature range of the experiments, but the brewhouse efficiency for the thinner mash showed a strong dependency on the temperature and was always better than the efficiency of the tick mash. That leads to the conclusion that thinner mashes perform better and allow for better extraction of the grain. Briggs also reports that thinner mashes can convert more starch but that most of the conversion potential is reached at a water to grist ratio of 2.5 l/kg [Briggs, 2004]"

"The thickness of the mash doesn't seem to effect the fermentability of the wort that is produced but thinner mashes can significantly improve the conversion efficiency. As a result brewers who see low efficiency from their mashing may try to use a thinner mash (3-4 l/kg or 1.5 - 2 qt/lb) as they were shown to convert more starches."