2nd BIAB low efficiency

Just wrapped up my second ever attempt at a BIAB session and wound up with about 55% efficiency, which is disappointing, but I know I'm new at it and will continue to improve. Can anyone lend a hand at pinpointing my issue?

Recipe
14lbs Pale Ale malt
11oz Crystal 60L

1.29oz Magnum (60)
1oz Magnum (5)
1oz Mt. Hood (5)

US-05 yeast

Mash at 152*
90 min boil

Batch size: 5.5 gal
Target OG: 1.070
Actual OG: 1.055

So, my 8.3 gal of strike water was heated to about 166* and when I mashed in, I pretty much got it to only 160*. When I eventually got to 152* I held it very steady at that temp for 60 minutes wrapped in blankets. I mashed out at 170* and held it there for 10 minutes. I collected just over 7 gallons pre-boil and after the 90 minute boil it finished at exactly 5.5 gallons. The bag I use is a 5 gallon paint strainer. The bag can support the weight of grain, but is perhaps to small to allow the grain to freely move in my 10 gallon kettle. My main concern for this particular batch is a poorly balanced beer that has strong bitterness without the malt body to back it up. Any thoughts or suggestions for my next go round? Thanks in advance!

With that much grain you would want to stir quite often during the mash to evenly disperse the mash, that helps a lot, Try even lifting bag out for a second, stirring mash and then put bag back in.

I second the stirring.

How was the crush? Sometimes crushing it twice will help efficiency.

I have been shooting for 70% efficiency and getting close most of the time. Not as high as I would like but I have only gotten over 75% once, and I don't quite know why. I second the stirring and the double crushing. The other thing is making sure your bag is big enough to line the whole pot giving plenty of room for the mash to get to the grain. Both of those improved things for me. Full volume extractions are also best although with big beers, which is mostly what I brew, I have been doing a batch sparge in a pot after the mashout. Still hoping for a regular efficiency of 75% but only counting on 70%.

How well did you get rid of the clumps in the grain?? That alone will kill your efficiency. If you don't mix well enough to break them all up, that's a major issue.

You have to mix the grain every 5-10 mins. It's totally a PITA, but if you want efficiencies is the mid 70's you have to sit there and mind the kettle.

And mix well.

j1laskey said:

You have to mix the grain every 5-10 mins. It's totally a PITA, but if you want efficiencies is the mid 70's you have to sit there and mind the kettle.

And mix well.

Click to expand...

It's been more than a while since I did BIAB, but I don't have to do that at all with my keg mash tun. I dough-in, equalize/stabilize the temperature, insert the thermocouple/probe into the mash and then cover and walk away. I check the temperature every 15-30 minutes during the mash (depending on the outside temperatures) and then finish processing the grain as normal (heat the grain bed to sparge temp), then use the auto-sparge (or another way to get the sparge water in) to sparge.

I don't biab but 15 pounds of wet grain in a 5 gallon bag seems kinda tight, no?

I don't think simply stirring more is the answer. I stir at mash in and maybe once or twice during the mash and have routinely been in the 70's. The bigger grain bill isn't doing you any favors, but as long as you don't have dough balls I don't see how more stirring will drastically improve anything.

The biggest boost I got was when I started double crushing and also when I've taken extra steps to drain the bag as much as possible. I throw mine in another pot with one of those strainer baskets and let it drain on its own for 10-15 minutes then give it a good squeeze. For the bigger grain bill, a small sparge would help as well. I've done that on occasion but didn't on my last batch and still hit my expected 70 on the nose. I think you get some pretty concentrated wort bound up in that bag and it's a big loss to leave it in the grain.

That's my guess anyway, especially based on you winding up with 7 gallons after a 8.3 gal strike. I only lost about 1/2 gallon on my last batch with about an 11 lb. grain bill.

I think optimizing each thing helps so stirring (about every 15 min for me) equalizes temperature, double crushing liberates more starch and enzymes for conversion, squeezing and sparging for big beers optimizes extraction and volume. Small grain bills get better efficiency (I've gotten close to 80 with a 5% ABV brew). I got near 70 with a 23 lb grain bill in 5 gals for the Russian imperial stout I did last week. Just tasted and got SG and it tastes rich and wonderful at 9.7 % ABV.

On the issue of 15 lbs in 8 gallons. That is way more water than the same grain bill in. Mash tun. I did 36 lbs in 11 gallons yesterday and sparged with 5 gallons for a double IPA yesterday and got around 68% efficiency. Yes it was crazy but I wanted to try a BIAB in a keggle for a 10 gal brew. Worked out well. Not recommended for high efficiency though

Also, in BIAB it is beneficial to squeeze the bag to get that good wort out.

Another thing that helps if your water amounts allow for it is when you take you bag out, have another pot of water at mashing temp to soak in. Let it soak in that pot for 10 min or so and dump that into the kettle.

Ie. This weekend i made a 10 gallon batch which i mashed the grains in 9 gallons of water, squeezed the bag, soaked the grain in 3 gallons in another pot, poured that into the kettle. I hit all my numbers that assumed 75% eff.

Thanks for all the replies, it's greatly appreciated. I think the double crushing and perhaps more stirring are definitely the first steps to take. I probably could squeeze or drain a little longer/harder, and the bigger grain bill in a tight bag probably didn't help things on this go around. Not sure if I want to go about doing a sparge, only because I ony have one vessel and one burner so long as I don't want to try and do some stove-top gymnastics at the same time. Part of what drew me to BIAB was doing AG without more than one vessel. As for the stirring though, I was afraid of stirring while it was sitting at 152* for fear of cooling the mash too quickly. I stirred a lot to bring it down to mash temp and then I stirred once more 15 minutes into it. Anyway, really appreciate the tips and I'm excited to keep trying and getting better. Any thoughts on the potential effects on my beer's flavor balance might be?

Who crushed the grain for you??

As for what to do with the batch now... Let it finish fermenting and then let it age a bit before you do anything with it. I'd give it 3-4 weeks in primary and see how it develops. You could get the higher IBU's to soften if you give it long enough. As for the flavors from the hops, those shouldn't be too far off (if at all) you'll just have a higher IBU/GU ratio. Giving it time to soften the IBUs will allow it to get back closer to where you wanted the balance to be. How long that takes is anyone's guess. When you're comfortable with it, bottle it up (or keg it) and let it age some more. It could be exactly where you wanted it to be in six months, maybe more, maybe less.

Your concerns over temperature loss while mashing with BIAB is one of the reasons I don't do it anymore. Another is how much grain I can lift, and hold, while it drains.