Poor BIAB Extraction Efficiency

I did a BIAB brew yesterday with a friend who's getting back into brewing and we got an extraction efficiency of around 55%. I was hoping we were going to be in the mid 70's. There were a few things my friend (I blame him) did that may have hurt the efficiency like: he didn't want to do a 10 min. mashout at 170, instead we did a 5 min mashout and stopped when the kettle temp was about 168. We stirred it pretty constantly but it was short. The second issue was that we didn't drain all of the liquid out of the grain bag. We let the bag drain over a colander for about 2-3 minutes and poured a gallon of room temp water through the grains for a mini sparge. After this I squeezed the grain bag pretty good but obviously there was still liquid and sugar in the grains. The recipe we used called for 13 lbs of grain so there was a lot of liquid that could of been added back to the kettle. The last thing was that we left about a half gallon of wort in the kettle at the end of the session because the hop pellets turned into mud and my buddy didn't want to strain anymore wort. Would these three things combined account for a 20% drop in efficiency? I'm thinking yes.

The mash out probably would not help any. The sparge helped a little. I think you need a pretty fine crush to get into the 70's with 13lb of grain.

Malticulous said:

The mash out probably would not help any. The sparge helped a little. I think you need a pretty fine crush to get into the 70's with 13lb of grain.

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Mash out helps tremendously with BIAB.

The only reason it could is incomplete conversion during the saccharification rest.

You're right that a longer mash-out would probably net you a few more points, but you'll see the biggest increase by letting your grain bag drain longer and squeeze the <bleep> out of that thing. If you hit your temps, you have nothing to fear regarding tannin extraction.

I've tried pouring water over the grain bag a couple of times, and was not satisfied at all. You'd get better results doing the dunk sparge that DeathBrewer details in his mega thread.

And, yes, if you had a poor crush, your numbers will suck. A lot of places crush coarser because the mash tun guys dont want a stuck sparge. At a minimum have them double crush, that can help a lot.

I routinely hit high 70s or 80 with 10 pound grain bills.

Recently I did a 17 pound wee heavy and got only 52%. I used the same technique and schedule. I suspect you are seeing the same limitation that I experience.

BHE has everything to do with water to grain ratios. Ideally you want half for the mash and half for the sparge. BIAB is not ideal for the mash, but for equipment it's cheap and easy to cean up--and it also makes great beer.

The problem with Deathbrewer's process is it takes two pots. BIAB is one pot, no sparge.

+1 on the downside. But here is the link to Deathbrewer's process: https://www.homebrewtalk.com/f39/easy-stovetop-all-grain-brewing-pics-90132/

Another link to check out: https://www.homebrewtalk.com/f36/biab-brewing-pics-233289/

Thanks for all the good feedback. Wolfman, you brought up a good point about the grain crush, my friend didn't ask the brew shop to do a double crush so that could of also been an issue. On my first and only BIAB session two weeks ago I got an extraction efficiency of 75% so there's no issue with BIAB not being efficient, the water to grain ratios for mashing don't seem to apply the same with full volume mashes. I wanted to also mention that I wanted to show my friend and wife what an incomplete conversion looks like with some idophor and cooled wort. I took out a little liquid at 30 min in on the mash and there was zero blue. I even had some pieces of grain husk on the plate? Has anyone seen conversion at 30 min? Thought that was kinda strange but I'm just getting into all-grain.

From what I understand, today's malts are so well done that they do indeed convert extremely quickly.

The caveat is when you start using adjuncts like corn and rice that have no diastatic power of their own it can slow down conversion, since you're essentially borrowing the diastatic power of your base malts to convert everything else.

I think it might have been Yooper that had done some tests on conversion times and found that most conversion was complete in 45 minutes or less.

From my biab experience mashout is very important. I dont squeeze the bag much anymore, but let it drain for about twenty minutes. I also double crush the grain. Remember to always have some spare dme on hand in case u miss ur target pbg. Ive seen no difference when attempting a mini sparge as you did.

Wolfman, I had the same thoughts on the malt just being really well modified. But conversion at 30 min. is just crazy! I think having a finer crush on the grain could also speed this up. I wonder if mashing times with BIAB could be cut down from 60+ to 30-45 to save a little time on the brew day?

AnchorBock, thanks for the good info on not seeing a big difference in points with a sparge. I'm still playing with the technique and will probably leave that out. The idea of having some extra dme on hand is a great idea! Just getting into all-grain so I didn't even consider that. Will have a little for the brew this weekend.

Cheers

At 30 minutes you could easily have conversion, but probably still have some long chain dextrins that more time is needed to break down to fermentable sugars.

Yeah, I'm not sure how shaving 30 minutes would really help you? I'm pretty busy getting my hops lined up for their additions, sanitizing the fermentation vessel, taking notes on PH, etc, and of course drinking to worry about shaving 30 minutes off.
Maybe I'm odd? :cross:

And God help you if you get into the European styles and start using Pilsner malt. That stuff needs 60-90 minutes to convert, followed by a 90 minute boil.