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2nd BIAB, Terrible efficiency!

Post #1 made 15 years ago
by opalko
Ok, this is my 2nd BIAB after brewing on a 3V system for a number of years. On my "old" set up with an "EasyMasher" (or homemade clone) I would normally get 75% efficiency - easily. My first BIAB I calculated the OG at around 1038 and ended up 1028-1030. This time I increased the grain bill and had an expected OG of 1050 (at 75% eff) and ended with a gravity of 1039 - 59% efficiency?!

The recipe
7 lb American 2 row malt
1 lb Crystal 40L
1 lb Amber malt
4 oz Corn sugar

.8 oz Goldings hops (5% AAU) - 60 minutes
.8 oz Fuggles (4% AAU) - 30 minutes

Wyeast #1469.

Grain crush same as I always use which is not a fine crush. Mash in at 151 F, 7.25 gallons, mash for 90 minutes, checking temp every 20 minutes. Temp averaged around 148 F. Added heat in small bursts occasionally if I saw temp dip to 146-7. Mash out at 151 F by pulling bag out and letting drip, squeezing what liquid I could get out of it by hand - (should I be running it up to 170 F first?)

90 minute boil, first 30 no hops. Ended up with 5.75 gallons wort. I don't really mind the gravity being lower - I prefer lower gravity brews but I'm not really sure why there is such a big difference in the gravity doing it by BIAB vs. 3V (I've brewed this one before).

Ideas?

Cheers!
Opalko
    • SVA Brewer With Over 100 Brews From United States of America

Post #2 made 15 years ago
by Mad_Scientist
You can mash out at 170 F and hold it there for 10 minutes, but that doesn't explain your poor effeciency. Your 2nd batch had 3+ pounds more with little gain.

Do you crush your own grain? With up to a 10 pound grain bill 84% effeciency is expected. I crush and my measured gap is .034" and I hope to get 84% on my 1st biab in a couple weeks.

Is that a voile bag you posted a pic of?

Richard
    • SVA Brewer With Over 100 Brews From United States of America

Post #3 made 15 years ago
by opalko
It is similar material to voile. It's more like a paint strainer bag material. I have a second bag I haven't tried yet made of voile. I have not adjusted the mill gap setting since going to BIAB from a 3V - I'll change that to get a finer crush and see what happens.
Cheers!
    • SVA Brewer With Over 100 Brews From United States of America

Post #4 made 15 years ago
by Ralph
Very odd opalko, poor efficiency seem to be the in thing of late!
Are you able to insulate your kettle for the mash? I'd do that, and thoroughly, then you don't need to be checking it all the way through the mash or adding more heat. I'd also look at a proper Mashout step, so yes, heat it up to 170F after the mash period is finished, then lift the bag out.
Also, as with any efficiency problem, check the fundamental measurements, so how ever you're working out mass* and volume, plus all of the instruments, so the thermometer, hydrometer, even all the way down to the timer.
The bag shouldn't retaining that much, however try the new one you have. Also the crush shouldn't be too problematic over 90 minutes, however slightly finer might help.
After that it might come down to chemistry, but let's leave that variable for the time being- it obviously worked with 3V.
Hope this helps!

* One novel way to test your scales is, next time you go to the supermarket, while you're there weigh a large assortment of goods on their digital scales, from small to large, write the weights on the item in felt pen. When you get home, do the same thing on your own- see how they compare. Obviously, the supermarket scales could be bung too, but there's more chance they will be calibrated regularly (here they face large fines). Try a few different scales, there's usually more than one in the fruit and veg section. If the store gives you any grief, just tell them you're air- freighting it to starving children and need to know the exact weight of every item, that should shut them up.
[center]Give me a beer and I will move the world. Archimedes[/center]

Post #5 made 15 years ago
by PistolPatch
Sorry to hear you had probs on your first one opalko :sad:. You are totally right though that there shouldn't be any major difference in efficiency between your 3V and BIAB. Most of us who have changed from 3V to BIAB have noticed a slight increase if anything.

I wrote a post the other day here on 7 reasons for poor efficiency. I think you will find on your next brew that the problem has suddenly disappeared. If it hasn't that would be very strange and we'd have to narrow things down a bit.

I still get an occasional brew that is wildly out and its always been one where I have only taken a single measurement. The other untraceable possibility is always of course, incorrectly weighed grain :angry:.

Good luck on the next one!
PP
Last edited by PistolPatch on 11 May 2011, 20:24, edited 5 times in total.
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