New Sack of Grain = Lower Efficiency?

[MI_Troll]

I recently purchased a new sack of Briess 2-row. My first batch on this sack I ended up with 62% efficiency, my norm is 72%, including batches made with 2-row. At the time I chalked it up to the high wheat content and it must have something to do with the wheat needing a finer crush, etc... I made two batches that day, the second with Maris Otter came in right at 72%.

Fast forward next brewday, first batch 2-row based, no wheat, comes in at 62% eff. I was shocked as I had closed the gap on my mill by 0.005" in hopes of getting closer to 75%. Second batch that day, pilsner malt base, comes in at 72% (obviously gap didn't help).

My question is, "Is this normal?" The only thing I can think of is that perhaps the grain itself is smaller/harder/has less sugars/is old and past its prime/etc... I am thinking that some sort of test people perform when purchasing a new sack of grain to compare against previous sacks?

Any insight would be welcome.

 

[ArcaneXor]

Let's just say that as the person responsible for ordering grains for the homebrew shop I work at, I would never order Briess base malts. I love their specialty malts, but their base malts, especially the Brewer's 2-Row, have gotten some poor feedback from customers, fellow employees, and last but not least, myself.

 

[wilserbrewer]

I do remember reading that some recent crops have low yield. Wouldn't think it would be as pronounced as you have observed.

 

[ajf]

Contact Briess for a Malt analysis for the batch you had bought. Malt analysis does vary slightly from one batch to the next, but your results show more than a slight variation.

-a.

 

[Cyclman]

This is way over my head, but Brewing Lager Beers goes into all the "science" of malts, efficiency, etc. Great book.

Somday, maybe I'll "get it."