Need help diagnosing poor efficiency--how's this crush look?

[MrSnacks]

This is double-crushed and has possibly settled out some.

Using this grain I got about 65% efficiency on my last batch. Pretty normal IPA, water/grain ratio was 2qts/1lb. BIAB, no sparge, hit my temps. Normal Minneapolis water profile, added a gram of Gypsum, half a campden tablet. I mash in a bag in a chest cooler.

It seems like my crush is fine-ish but I can't quite figure out why else I'd be getting poor efficiencies.

 

[Devin]

Crush looks okay, but you could go finer with BIAB. Are you squeezing your bag when you pull it (or at least let it drain for a long time)?

 

[Rockn_M]

Crush seems fine. What temp and for how long are you mashing for?

 

[MrSnacks]

Crush looks okay, but you could go finer with BIAB. Are you squeezing your bag when you pull it (or at least let it drain for a long time)?

Yep, I've got a carbiner setup on my porch that I hang the bag from. I'd love to grind it finer but this is my neighbor's mill with a hand crank, it took two passes to get it this fine. Hopefully getting my own mill soon.

Crush seems fine. What temp and for how long are you mashing for?

Mashed at 150* for about 75 minutes. Lost more heat than I normally do but that shouldn't matter much.

 

[Rockn_M]

That is ok.

65% isn't that bad with BIAB. I usually get around 65 to 70%. That might be all you can get.

 

[FuriousE]

That is ok.

65% isn't that bad with BIAB. I usually get around 65 to 70%. That might be all you can get.

Definitely not all you can get. I usually get at least 75%, and many people are hitting 80's.

 

[MrSnacks]

Idle thought: could the grain bag have any effect on efficiency? I can't imagine it would as long as it's porous, but just trying to think of variables.

 

[rmyurick]

I agree with RocknM--a lot of homebrewers that fly sparge only get 74-75% efficiency.

 

[FuriousE]

I agree with RocknM--a lot of homebrewers that fly sparge only get 74-75% efficiency.

I get about 80% when I fly sparge, and about 75% when I BIAB. And I don't do anything special. Double crush for the BIAB. My crush looks pretty similar to the pictures above, maybe slightly finer.

 

[RM-MN]

I also BIAB with northern Minnesota water and I get 80% efficiency no sparge of 85% with a small pour through sparge of cold tap water. This is what my grains look like. I use a Corona mill set as tight as it will go and still turn the crank.

 

[MrSnacks]

So here's another possible variable: could it be pH? According to my water report, Minneapolis's average pH is 9. That's obviously on the high side but I'm not sure it should matter much.

I'd also concede it could just be measuring error but I am careful to correct for temperature in my gravity readings.