Higher than expected efficiency?

porkchop · September 2, 2014, 4:47pm

First, let me start out by admitting I haven’t gotten a water report yet–It’s on my to-do list, though!

Over the past 10 all-grain batches, I was getting a very consistent 72% efficiency and getting very close to my target gravities. Grinding with a corona-style mill, mash in a cooler with false bottom and batch sparge, and with a mesh bag and a dunk sparge. Regardless of the specific technique, the end result was very consistent.

However, on my last two batches, a porter and stout, I seriously overshot my target gravity, and to hit the numbers in Beersmith I had to up the efficiency to 87% and 82%, respectively. These two specific recipes called for calcium chloride, and it was the first time I used it with my well water.

I’m a rookie at water chemistry, but is it possible that a 5-gram addition of calcium chloride could end up with that big of an efficiency bump given a certain unknown water chemistry? I can’t think of any other differences from brew day.

If anyone has any other ideas I should consider, I’m all ears. My goal is consistency, not super-high efficiency, so whatever I can do to make the end result match the recipe would be great.

mattnaik · September 2, 2014, 4:55pm

Is that mash efficiency or total brewhouse efficiency?

porkchop · September 2, 2014, 4:59pm

Mash efficiency, I believe.

mattnaik · September 2, 2014, 5:10pm

It’s possible the added calcium chloride lowered your pH to a level where you would get better efficiency but I don’t know enough about the chemistry side of things to know if you could experience a 15% increase. My gut tells me no but that’s just a guess.

Is it possible you improved flow or eliminated dead space in your mashtun?

porkchop · September 2, 2014, 5:41pm

I agree - that big of an increase struck me as odd, but I can’t think of any other differences. If it could have made that big of a difference, I would have thought my previous brews would have suffered from significant issues with tannins or other off flavors.

With mashing in a bag in a cooler, I literally have no dead space, and the only loss I have is from absorption. It’s a pretty awesome way to mash (thanks Dave!), and I would chalk it up to that, but the porter at 87% was done in my mash tun with false bottom/batch sparge. The stout was at 82% and done with the bag in the cooler.

I must be missing something. Not complaining about the improved efficiency, but without knowing how to account for it I don’t want to switch all my recipes over and end up missing on the low side.

mattnaik · September 2, 2014, 5:49pm

Off the top of my head the only things I can think of that would cause such a big boost in efficiency would be either a much better crush or an error in measurement of something (e.g. grain weight, volume of runnings, gravity of wort).

porkchop · September 2, 2014, 7:47pm

Thanks Matt, my head is in the same place, which is why it’s bothering me. It’s hard to plan a recipe when you’re getting anywhere from 70-85% efficiency.

I’m sure the fineness of the crush with a corona-style mill is all over the place, so the simplest explanation is that the crush was probably a little (or a lot) finer than previous runs. I’ll just have to try a few more batches and see if it falls into a new pattern.