1st BIAB horrible efficiency!

58%...if that.

Here's how it worked. I was aiming for 2.5 gallons of a 1.090 beer through BIAB. I dropped my 8LBS of grain (7lbs MO, .5lbs Munich, .25 Carapils, .25 Crystal 40) into a bag and then into 4.5 gallons of water. Before I dropped the bag, I pulled the water off at 165F, hoping to get it set at 153F. I think my thermometer is slower than the temperature rise of the water, because when I dropped the grains in, the water steadied at 160F! After about 10 minutes of stirring and blowing on the water, I finally got it down to about 155F. I was okay with this because I figured I'd lose some degrees. I covered the pot with a heavy blanket and let it sit for 30 minutes before I checked the temp. It got down to 148F! I set it back on the stove and heated it up again to 155F. At the end of 60 minutes, it was back down to 148F. I pulled the grains and gave them a squeeze. Boiled for 60 minutes and only got 2.25 gal out. My OG was 1.070! Far less than expected. Especially because I heard that BIAB is supposed to be the best with efficiency. Here are my thoughts as to possibly why...

1) When I dropped the bag of grains in, the temp was too high. Possibly preventing the enzymes from doing their work, like a mash out.

2) I dropped the bag of grains in the water (tied at the top), instead of dropping the grains into the pot with the bag over the edges of the pot. I feel that I may have made one big dough ball, with water not being able to penetrate the interior. I tried to stir it and poke it around so it got a lot of water penetration, but this may not have been good enough.

3) The fluctuation of water temp really worried me. Mainly because I didn't know what I was going to get, but I doubt this is the reason.

4) I never used any sort of sparge/rinse water. I tasted the grains afterwards and they tasted bland, but there may have been some sugars still in there that I missed.

This is all I can think of. Any other ideas why my efficiency was so bad? Still a good 8% beer (it dropped to 1.010), but disappointing to be so far off. Thanks for the input.

Did you do the crush yourself? BIAB crush can be much finer than a store would crush it since you don't have to worry about stuck sparges.

Also, the temp fluctuations are all over the place, you might have had lots of unfermentables because of the long span of high temperatures.

Finally, how certain are you on the gravity reading? Was it all temp corrected, have you calibrated the test equiptment?

I doubt temp influenced your poor efficiency. You have to be around 170 to cut off the main enzymes from working. You were all over the board, but easily within range. If you ever have doubts about conversion again, buy some iodine and test the mash. Also, make sure your thermometer is accurate by comparing it to others.

I would place it on the no sparge or the bundled grains. No sparge will often drop efficiency down 10 percent (maybe less in BIAB). Another cause could be your crush. You should have a really fine crush for best efficiency.

Addition: Unfermentables would influence the final gravity.

I think you're confused about BIAB's reputation for efficiency, but I'm a noob myself so I'm sure somebody with way more experience will chime in and clarify that.

Regardless, your efficiency is very low. I just did my first BIAB -with quite a few mistakes- and my efficiency was 65%, not high but not nearly as low and I think the biggest reason for that was all the spilled wort on top of my stove (the grains PLUS the water were supposed to fit in there!! what a freaking mess )

From my VERY limited experience I think Number 2 and Number 4 above are the most crucial. I was surprised of how much sugar I got on the rinsing pot. I thought it would be very, very thin and it wasn't, not even close. I actually think it was thicker (or at least darker) than the first one. And I think it's very likely that yes you made a huge dough ball, but you already figured that yourself, as well as how to fix it.

But hey! You already have the first one under your belt, and if you're like me and learn the most by doing that's a big thing. Next one will be much better

I think both the lack of a sparge and the bundled grains effected your efficiency. I had a very similar story after my first BIAB session, because I had split the grain into two seperate grain bags. The key to BIAB is allowing the water to flow freely through the wort.

Also, I check the temperature and stir every 15 minutes. Just leave the pot on the burner, it'll make it less work intensive. Try mashing longer as well. I usually mash for 75min and then do a mashout at 168 for 10min.

Thanks guys. I can't wait to replicate this recipe and give it a shot again. I'll double mill the grain and let them free float in the water. Give it a quick sparge and check out the difference. Too bad I'm broke right now otherwise it'd be done tonight!

Unless you have a long stem thermometer, your temperature was the temperature of the top of the grain, not down in the middle toward the bottom. You have to have the grains loose for the water to mix properly with them. I use a paint strainer bag with an elastic top that I can stretch over the top of my kettle and it will stay there. The bag is large enough to reach clear to the bottom of the kettle and I put it in there when the water is at the right temperature, then stir the grains into the water, making sure that there are no dough balls. If you have a sufficiently large kettle you can use the whole amount of water at once and forget sparging. Have the grains milled fine and when the mash is over (60 minutes) you pull the bag of grains out and let them drain and then squeeze out all the water you can and you should get much higher efficiency.

x2 on the no dough balls. I would imagine that BIAB would cause alot of dough balls. For your next batch try a bigger grain bad, and see if that helps. However, I would not squeeze the grain bag too much. Squeezing too much could cause you to extract tannins and grain husks.

slomo said:

x2 on the no dough balls. I would imagine that BIAB would cause alot of dough balls.

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A proper biab is much less prone to dough balls (for me, anyway); the bag should be big enough for the pot to fit inside of, so the grain is really free-floating in the water (the bag is fully lining the insides of the pot, not any smaller). With the thinner mash of BiaB, things are less compacted and clogged than in a thicker 3-vessel mash.

OP's bound bag certainly sounds like a problem.

Well now that I've got that figured out, how to I maintain a constant temp? I use an aluminum pot, which I've heard retains heat well, but even wrapped in a thick wool blanket, the heat still seems to drop fast. Any ideas there? If I kept my burners (electric) on low, would that do it or do you think it would continue to raise the temp of the wort?

It's difficult to keep the temp constant on low (although probably would be more constant than the other method. Toward the end of my BIAB experience I used a well-insulated sleeping bag that would only allow a drop of 3-5 degrees. Just be sure not to disturb it, (okay, maybe at the 30 minute mark). This would also mean that you have to make sure the grains are mixed really well at the beginning.

pre-heat your oven to 200 degrees, turn it off, and then put your kettle in there. Should help if it fits. good luck.

captainL said:

pre-heat your oven to 200 degrees, turn it off, and then put your kettle in there. Should help if it fits. good luck.

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That's a good idea. I'm not real familiar with how dry heat reacts with wet heat, but if the dry heat is over your set mash temp, would this raise the temp over the 60 minute rest?

trevorc13 said:

That's a good idea. I'm not real familiar with how dry heat reacts with wet heat, but if the dry heat is over your set mash temp, would this raise the temp over the 60 minute rest?

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I've done that a few times, shouldn't really raise the temperature. Invest in a good digital thermometer. I use a Martha Stewart cooking thermometer and it works great, I can even set an alarm to go off if it hits a certain temperature. And it won't melt if you put it in the oven!

A 5 or 10 gallon igloo-style cooler works well to keep the temperature steady, also. If you're doing a BIAB, you don't need to modify it. Then when you're ready, you can fit the false bottom/ball valve assembly at a later date to make a "real" MLT. My old igloo cooler keeps the mash temp stable for an hour for a good BIAB mash. Then sparge with a soak in 170 degree water in your brew pot. I used DeathBrewer's BIAB method but substituted the cooler for the smaller pot. Good luck!