Brewhouse (in)efficiency

The gap on your mill slipped or is wider than you used to do. Tighten the gap and efficiency will increase.

 

My mill is set at .034 to .036", give or take.

 

I don't measure my gap. My advice is to set it "tighter than you think you should". Then make a couple of batches, and as long as you don't run into a stuck mash, keep it there, or try going even tighter. The tighter the gap, the higher the efficiency and the less time you need to mash as well. With a good tight gap, I've been mashing every batch for just 40-45 minutes for the past 11 years or so and still get an average 82% efficiency.

 

While grain crush is a common cause of mash efficiency/brewhouse efficiency problems, it's not the only possibility. A few questions @magoo0903...

- Has anything in your process changed (besides potentially loosening the mill gap) since your efficiency was better?

- Did the issue coincide with the introduction of HERMS?

- When you were typically getting higher efficiency, were the batch sizes and expected gravities the same as the recent problem batches? (Larger batch sizes are more efficient because some losses are constants spread over the larger volume. Higher gravity batches are less efficient, because the ratio of total water to grains is less, leaving more sugars behind in the mash tun.)

- Did your post boil volumes match the planned volumes?

 

Amen brother . . . measure your gap just like you measure your strike water or grain weight. A simple feeler gauge does the trick:


FWIW, when I switched from false bottom to bazooka screen my efficiency jumped two points.

 

False bottoms definitely have their uses, but depending on design/installation, they can cause some pretty large dead spaces. I use a "toilet braid" in my mash tun.

 

One other thing that would cause a little difference is if the calibration of your thermometer is off. Take care. ( I had this issue! )

 

Toilet braider here, hahahahahahha, but all the above can be looked at to see if your efficiency can be lifted.

 

That is very wide. Tighten up.

 

Have you measured the pH? It could be a factor, as well as the smaller batch sizes and mill gap.

 

I agree that the first place I would look is the mill gap. But if you don't have a feeler gauge, you might not need to get one, as long as you have credit cards in your wallet (and what homebrewer doesn't?). I've been told that the width of a credit card is a good place to start. That's what I used to set my gap and I haven't looked back. Anyhow, it's a starting point, and if you don't like it, make it a little tighter or a little looser and try again.