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Brewing Topics => Brew In A Bag (BIAB) => Topic started by: kedro38 on March 17, 2014, 03:58:35 PM

Title: BIAB Fermentable Sugar Extraction
Post by: kedro38 on March 17, 2014, 03:58:35 PM
I am glad I started all grain brewing using BIAB but I never really understood why BIAB is supposedly less efficient at the fermentable sugar conversion… just wondering?
Title: Re: BIAB Fermentable Sugar Conversion
Post by: morticaixavier on March 17, 2014, 04:22:12 PM
not the conversion but the extraction.

Brewhouse efficiency is a product of two different measures of efficiency. There is a theoretical maximum amount of sugar that can be converted from a finite amount of grain. let's say that's somewhere in the vicinity of 38 points per pound per gallon. if you know exactly how much grain is in your batch and exactly how much water is in your mash and you take a gravity reading of the wort you can determine your Conversion Efficiency. this can and should be close to 100% by the time you're done with your mash and I don't think BIAB would results in any lower conversion efficiencies. In fact, I think with the generally thinner mash you might be better off here.

The second part is Lauter Efficiency and this is where BIAB CAN (I stress CAN) reduce your efficiency. Any sugars you leave behind in the grain reduces your lauter efficiency and therefore your overall or brewhouse efficiency. The more you rinse the grain the higher your lauter efficiency will be so when BIAB or no sparge, because you don't rinse your grain, you can see some reduction in lauter efficiency.

This is actually the genesis of fly sparging. back in the day everybody batch sparged and someone noticed that the more batches the more efficiency one got out of a grain bill after a while this became continuous sparging.

**EDITED FOR SPELLING**
Title: Re: BIAB Fermentable Sugar Extraction
Post by: kedro38 on March 18, 2014, 08:00:09 AM
Thanks morticaixavier… and I corrected the header.
Title: Re: BIAB Fermentable Sugar Extraction
Post by: morticaixavier on March 18, 2014, 08:51:52 AM
glad to help