How important is mash thickness?

[kombat]

I usually brew 5 gallon batches, but every now and then I like to do a little 1 gallon BIAB batch because I can do it inside on my stove, and it takes much less time. But tonight when I was doing a batch (Imperial Wheat IPA), it occurred to me that I might not be mashing properly.

I use BeerSmith to design my recipes, and for this batch, it instructed me to heat 8 quarts of water to 154 F, then dough in the grains and settle at 148 F. But this results in a very thin mash. This recipe only has about 2.75 lb of grain, which means the mash thickness works out to 2.91 qt/lb of grain. I know most brewers target between 1.25 and 1.5 qt/lb. In this case, I mashed for 90 minutes, then removed the bag and heated to boiling.

Should I instead be mashing with less water, resulting in a thicker mash, and then topping up to my pre-boil volume with plain water? Or is it not really that much of an issue?

 

[Onkel_Udo]

Change your equipment profile to BIAB in BS.

Mash thickness, within reason, is so unimportant with highly modified grains that it requires no real adjustments. As long as you hit your temp and are not using a bunch of under-modified adjuncts, do not worry.

 

[TexasWine]

2.91 qt/lb is fine for full volume BIAB.

 

[Mike_kever_kombi]

Change your equipment profile to BIAB in BS.

Mash thickness, within reason, is so unimportant with highly modified grains that it requires no real adjustments. As long as you hit your temp and are not using a bunch of under-modified adjuncts, do not worry.

I would add the caveat "and your PH is within range"

If you have a high PH to begin with, a really thin mash may not have enough grains to offset, leading to more Tannin extraction.

 

[Onkel_Udo]

I would add the caveat "and your PH is within range"

If you have a high PH to begin with, a really thin mash may not have enough grains to offset, leading to more Tannin extraction.

Wouldn't you have the sam theoretic isse if you were doing a traditional sparge method without correct?

 

[Mike_kever_kombi]

While it is important for for a traditional mash, it is probably more so for a BIAB where the contact time is going to be much greater than with a batch sparge. A fly sparge would be more important than a batch sparge.

But yes, I would say proper PH is important regardless of your method

 

[TexasWine]

I've always read that excessive tannin extraction requires a pH issue (above ~6) AND temps above 170F. Not to say that you shouldn't strive for the proper mash pH, but I'm not sure tannin extraction is the main reason why.

I beleive the real driver, as suggested by Braukaiser's chart, is enzyme activity. Too high or too low, and you just dont get the conversion you need.

My 2 cents. Learning as I go here so someone chime in if I'm way off base.

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[tomaso]

Just my two cents but I thought that the more water (within reason) the higher your efficiency will be, I. E. No problem, only advantages

 

[RM-MN]

Just my two cents but I thought that the more water (within reason) the higher your efficiency will be, I. E. No problem, only advantages

I usually use a 2.75 ratio but recently I did a bigger beer and needed to use a 1.5 ratio to keep from going over the top of my pot. The next day I did a small beer and the ratio was 4. My efficiency stayed at 85% for all of them. The big beer took more sparge water to get to my preboil amount. YMMV