New sack of grain = poor efficiency.

[jaydubber]

Hello brewing friends. I recently acquired a new bag of Thomas Faucett Maris Otter and have had a hard drop in kettle efficiency with the bag. I can't say I've used TF exclusively in the past, my bags have probably been a mix of TF and Baird, but I've never noticed any difference in efficiency, either between maltster or between sacks.

My efficiencies are generally between 75% and 78%, with the new sack i've hit 60%, 62% and 61%. I thought the first 60% was a fluke, and that I screwed up or mis-measured, but when the second came out at 62% I adjusted my expected efficiency and hit numbers exactly the 3rd time. Nothing has change in my equipment or process. I brewed a lager in between the above batches and hit my normal 75% for that recipe, so I'm pretty sure this drop is related only to the new sack of grain. Also, these 3 under performers had target OGs of 1.055, 1.058 and 1.073, so nothing too crazy, and consistent numbers across.

So, I'd expect small variances between sacks, but have you guys experienced anything like a 15% drop from one sack to another?

-JD

 

[dryboroughbrewing]

have you verified that your mill gap hasn't slipped?

 

[jaydubber]

have you verified that your mill gap hasn't slipped?

Yep. That was one of the first things I checked after the first lousy batch.

 

[IslandLizard]

Could the malt be very old? There should be a batch number printed on the sack, so you can check.

I never noticed any less efficiency with that malt, even after it's 2 years old.

What is your milling gap? Did you look at the milled grist after crushing? Maybe these kernels are smaller or more flexible (high moisture), and don't get crushed properly.

Maybe try a small test mash, like a pound at 148F, and measure the gravity at 30', 60', and 90'. If the gravity still goes up after 60' it maybe low on enzymes from age and/or poor storage. Mash in a 3/4 or 1 gallon pot in a preheated but turned off oven.

 

[jaydubber]

Could the malt be very old? There should be a batch number printed on the sack, so you can check.

I never noticed any less efficiency with that malt, even after it's 2 years old.

What is your milling gap? Did you look at the milled grist after crushing? Maybe these kernels are smaller or more flexible (high moisture), and don't get crushed properly.

Maybe try a small test mash, like a pound at 148F, and measure the gravity at 30', 60', and 90'. If the gravity still goes up after 60' it maybe low on enzymes from age and/or poor storage. Mash in a 3/4 or 1 gallon pot in a preheated but turned off oven.

Unfortunately I tossed the bag before checking the batch number. I got the sack from a local HBS that turns over a lot of product, so I'd be surprised if it's all that old.

Mill gap is .035, which I use for everything. The grist looks normal, and a different Pilsner batch I did in between these came out at 75%, so that's normal. The only thing that looks different about this sack is it seems to have more chaff than I usually see, but I wouldn't guess that accounts for 15% loss.

Good idea on the mash test for conversion beyond 60 minutes. I'll give that a whirl.