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First two BIAB batches low efficency (55-60%). Top reasons for low?

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Illini Rookie:
First off, I hope this is the right spot. I consider myself all grain now even though I don't have all the extra equipment.

First batch with BIAB was an IPA that ended up around 55% calculated efficiency. Luckily, I was targeting a little higher gravity so the low efficiency didn't kill me.

Second batch was a Kolsch that I also targeted high. Again, I ended up low, but this time with some mild improvement (60%). Both efficiency numbers were gotten by changing the efficiency number in the brewers friend recipe calculator until my OG matched the program.

A couple of notes about my set-up and process.

10 gallon brew pot, custom bag (fiance sewed it for me) that fits well over the edges.

Grains were sent through the mill at the homebrew store, so even though I have read that grain can be practically pulverized without any fear of tannins due to the mesh of the bag, I had 'regular' crushed grain.

Mashed between 154-150 for the IPA, and 152-146 with the Kolsch. Both were stirred periodically and the temp brought up by boiling water when it dropped. I had three different thermometers (brew pot, probe, and a digital stick) and they all pretty much were around the above temps.

Mashed for 70 mins on the IPA and 80 mins on the Kolsch.

No iodine test because I don't have any.

Small sparge of grains on IPA after I pulled the bag (~2 qts at 170 over spent grains). Kolsch grains sat over a strainer, and I added all the drippings back.

Both batches ended up at the volume I wanted, so I don't think it was an issue of adding too much water.

No pH taken during the whole thing either. No dark malt to bring acidity down, but I don't think my water would lead to higher pH (near Boston, MA).

Sorry for the length, but I wanted to be thorough. What are the top reasons I could of ended up with a low efficiency.

brew1314rw:
I do not do a BIAB but the times I have done a partigyle the first batch is usually around a 60-65% efficiency in my system.  Also, as I go up in gravity my efficiency does go down quite a bit as I do not have a really large boil kettle to collect a lot of sparge and boil it down.  I would expect 55-60% to be fairly typical for a higher gravity BIAB.

sparkleberry:
when i biab-ed, i would mash for at least 90 minutes. i built a "jacket" for the kettle out of 1" foam sheathing from home depot. it held temps pretty well. i never sparged and never worried about ph and still hit about 72-74% every time. i also found i needed to hit higher strike water temps to hit mash temps i wanted on my system.

my first suggestion is to mash longer. the research i did and the results i had show 90 minutes plus for a biab mash is a good thing. second suggestion, mill twice if you can. i did and while it didn't noticeably add points to efficiency, it didn't take them away.

hope this helps.

cheers.



erockrph:
A) Crush fine
B) Squeeze the hell out of your bag.

I'm still dialing in my BIAB setup, but my efficiency has been as low as the 60's in brews where my grain wasn't crushed fine/twice and I wasn't squeezing super hard. I've had efficiency as high as 80% on a 1.110 barleywine, but the grains were crushed extra fine and I really made sure to squeeze as much as I could out of the bag.

amh0001:

--- Quote from: erockrph on January 21, 2013, 08:17:10 PM ---A) Crush fine
B) Squeeze the hell out of your bag.

I'm still dialing in my BIAB setup, but my efficiency has been as low as the 60's in brews where my grain wasn't crushed fine/twice and I wasn't squeezing super hard. I've had efficiency as high as 80% on a 1.110 barleywine, but the grains were crushed extra fine and I really made sure to squeeze as much as I could out of the bag.

--- End quote ---

I have been doing 2.5 gallon BIAB's now for about 10-15 batches. what erockrph said is what I would recommend. Also If you have a lot of adjuncts in your recipe you wont see as good eff at a 60 min mash.

I usually just do 60 and compensate a little grain if I know I have a lot of adjuncts. IE oats, wheat.

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