Efficiency question

I'd say yeah, depending on the difference in grain weight, the double crush and being able to squeeze more wort, you'd see a significant increase. Also if you brewed different styles (dark vs. light) the mash pH could be a factor here.

My understanding of BIAB is that 60 can actually be fairly normal. The one BIAB batch I've done was 66%. Lower isn't uncommon either, based on my understanding.

 

I don't BIAB but that seems awefully high, is it possible that the temps were drastically different and you aren't adjusting the hydrometer readings for temp?

 

It's not so much about higher pH, more about the range. You'll get better results when your mash pH is between 5.1-5.4 according to Palmer. So depending on the darkness of the malts (darker malts can increase acidity), if you already have slightly acidic water and brew a dark, roasty beer, that could throw your pH into problematically acidic territory, negatively impacting your extraction and conversion.

Or if you have very basic water and brew with grains that can increase acidity, that could bump you into an optimal range, improving mash efficiency.

I do agree that 96% seems insanely high, but I suppose it's possible. I've gotten into the upper 80s.

 

Well, it does seem as if some kind of miscalculation would be more likely than 90% efficiency. And there are two calculations that spring to mind as directly relevant: 1) hydrometer calibration and measurement, which you feel confident were correct, and 2) ingredient measurement. If, for example, you started with 9.5 lbs two row rather than 8.5, that could explain the bulk of the difference.

 

Did you not sparge your other ones at all? When I've done biab I usually just do no sparge and my efficiency is around 60 or lower. Sparging will definitely get more sugars out so that will contribute to higher efficiency. But again 96% seems mythical.

 

Did you include your sugar addition in the original calculation? That would make a really large difference in calculated efficiency.

 

Yes, if you dump everything in and you have a gallon worth of solids in your fermenter it will inflate your numbers. ie 88% efficiency at 5.5 gallons (calculated in BS2) and 70% efficiency at 4.5 gallons.

You are most likely off by your volume. Once you bottle/keg/rack your beer, you will know for sure.

I should mention also: if you've done a 2 gallon sparge, you almost certainly will not have that high of an efficiency. Rule of thumb being that sparge volume should be at least as high and is often higher than mash volume. For this recipe for instance, I would probably mash with about 3 gals of water and sparge with about 5 gals of water.

The good thing is your efficiency should almost certainly be higher than 60%, so you are moving in the right direction!

 

In my experience, a thicker mash will hold heat better than a thinner mash. The larger sparge volume also gives you more time to rinse the grains of remaining sugar, and therefore better efficiency. However, you're right - if your mash tun has a lot of head space, that can cool your mash quite a bit faster. Good luck!

 

You should not be including the sugar in your calculation of efficiency. You should subtract the gravity added by the sugar from the gravity that you have in the fermenter and use that figure to calculate your extraction efficiency. In other words of you are using the OG of 1.064 in your calculation then you're going to get an erroneously high figure.

 

Think of it this way, efficiency is a measure of how much sugar you were able to extract from the grain, so the calculation should only include sugars that were extracted from the grain, not sugars added from other sources.