Efficiency/Gravities.. Frustration

After finishing an AG batch yesterday, i started calculating my efficiency and ended up significantly less than previous batches. I had changed some things, most significantly, milled all the grain myself. But for once i acutally pretty much hit my target mash temps, shooting for 156, mashed in with 170 and held from 170 down to 155 for the 60 minutes of mash.

I was targeting 1.047 on the preboil gravity, and ended up at 1.032. Any thoughts on what could cause this. I am leaning towards a bad milling and a need to dial it in better?

Also, i believe that i mis-estimated my grain absorption rate, and therefore probably diluted it too far.

So after corrections using DME to bring the gravity up i ended up within a few point of FG.

Any thoughts or advice on dialing in the mill, (corona style), and bettering hitting the numbers.

Trying to get my stuff straight before my next batch in a couple of weeks

I also mill my own. In general, my efficiency has gone from dismal to great since making this change. I mill so that the kernel of the grains are all about a millimeter and a half in size on average. Still, sometimes I cannot quite explain my efficiency. I brewed a Hefeweisen about a month ago and I planned on a 1.050 OG. I weighed my grains with the intention of having about a 75% efficiency. I ended up with a 90%+ efficiency. Oh well. OG ended up being 1.070, that'll be a GOOD Hefeweisen. Contrary to this, last week I brewed an IPA. I planned on a 1.075 OG expecting a 75% efficiency. My efficiency ended up sucking real bad. I even tried to augment the poor mash efficiency by adding pure amylase, to no effect. In the end I had to add 3lbs of my homemade amber candy syrup to get the gravity to an acceptable number. That'll be an interesting beer. Eh, hop it to hell and back and it'll be great.

Water PH, thermometer accuracy, and acts of God all have an impact. Once you figure out how to master this process, let me in on the secret too.

Best regards

I think grain crush has a huge impact. I used to do a fairly thick mash, but I've had better luck with a thinner mash. My numbers got much better.

Any chance your thermometers may be off. You're mashing fairly high already at 156F. Any chance you're going in too high and that's impacting your mash?

I always do a slow stepped mash. I start at 140F and slowly work up to 155F over the course of an hour. I stop at the 155F temp and let it rest. I usually always get high efficiency. For some reason I didn't this last weekend. I was using a mix of grains, not my usual all 2-Row that I'd use for an IPA. It is almost as if the Pilsner malt didn't convert. My first time using this malt in any amount. The 2-Row batch I used in this is proven to produce good mash. Who knows, I certainly don't know why it was a poor efficiency. The local water supply certainly doesn't have a rep for consistency. Maybe the PH was all wrong. It's possible because that is one factor I didn't measure. And it persisted to have a poor conversion despite me adding pure amylase enzyme to the mash.

pH and mash thickness play a part in mash conversion but it's pretty minor unless it is way off. The quality of the crush is usually the problem with low efficiency. Two things for you to think about for your next batch. Tightening the mill is the first and the tighter you go the higher the efficiency and the less time will be needed for conversion but as the grain particle size goes down the husks become more torn up and with that comes problems with draining the tun. You've probably heard of stuck sparges. You really don't want to deal with that if you can avoid it.

With your mash tun, the grain husks must form the filter bed to keep the grain particles out of the boil pot. For that you need relatively intact husks but they get torn up if you tighten the mill since they are dry and brittle. The answer to that is don't mill them dry and brittle, dampen them a bit. It doesn't take much water to make the husks tough, tough enough to withstand the grinding plates on your Corona mill.

One other method to deal with the finer particles and torn barley husks is to add rice hulls to the mash tun. Without going through the mill, these will be intact. It doesn't take a large amount to augment your grain husks and they are quite inexpensive too.

Thank you all for the input. I use beersmith so in the hopes that it knows more than I do, I used it's suggested mash in temp at 156, with strike water at 170. I am using a rectangular cool mash, which I know have issues maintain in mash temp. A step up mash would probably be a good idea I will have to look further into that. I have a few ideas on how to better deal with heat loss.

As you hit on, I was concerned with over milling the grain and ending up with flour. TBH I am still trying to get the technique down on the milling, but with 50# of 2 - row sitting in containers I guess I will get it down. Using a bazooka tube also doesn't seem to yield the same grain bed results in so far as setting. I get relatively clear wort but always has some particulate in it. I usually strain it through cheese cloth into the kettle, then stating again into primary through a course mesh.
I have found that with my chiller I am getting a good cold drop to pitching temp which has helped with clarity.
In the interest of consistency I have been using at least 5 - 7 gallons of bottle spring water to try to eliminate any off flavors from local tap water.

I did a bitter last time and was well with in the target range for my gravities. The biggest difference was I bought pre milled grain for that

After reading your comments I am leaning towards grain crush at the #1 issue. We did some modification to the mill before this batch so I have to get the accuracy down.

Thank you.

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I also, I think the mash ended up too thin in the end when I tried to account for grain absorption and it wasn't as much which, if somebody can confirm, will dilute the wort lowering the gravity.

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How are you sparging? What was the first running gravity? The sparge gravity? Use a refractometer? Did you mash out? Temp of the sparge water? The crush could be it, but too many people assume the process is flawless and if only the crush was finer, the efficiency would go up.

Batch sparge, had horrible luck with fly. Gravity of net first running and sparge just before it went in kettle. Using a hydromeyer, temp was at 120 - 130 before boil kettle. But it was corrected to 68. I mashed out with first running a plus x qts to attempt to account for grain absorption. Then second step sparge with I want to say 150 to 160 degree sparge water, but I don't have the numbers in front of me. I don't profess to have perfect process, which is why I am on here trying to get it better. I think the crush may be a contributing factor. But I am open to other ideas to improve my method.

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That's how I do it. Before first runnings I do the mash infusion step which adds water to account for grain absorption to yield close to equal runnings. So after mash at ratio, been mashing at 1.50 qts/lb I add 185-190 degree water mash infusion to get the grain bed up close to 168. I give that about a 30 second stir and let sit for 5 or so minutes and then drain. Then add 185 water for sparge, stir and I let sit for another 5 minutes and drain. Vorlaufing at the correct times. Maybe raise the mash infusion/sparge water to gain a few points. You can get that water pretty hot without the grain bed going over 168. Also, I never had good luck using bottled water. Maybe try filtering your tap water with carbon and treating for campden for any residual chlorine or the presence of chloramine. Unless you know your water is unfit for brewing that may be worth a try. You can check your city's water report online to at least get an idea of what's in it. Also, get a refractometer. That's my best advice of this post. Vital tool. So much easier than using a hydrometer for readings during brew day. I'm not sure how much I'd trust the hydrometer until the sample was down at 70F or in the low-mid 60s ideally.

That's what I was shooting for with an addition after the mash was to bring up the mash out first step. But I think I over did it. Last time I think I also let the second sparge stage sit for 15 min and rest at that. Which may have helped. I think I have to dial in some of the steps with my system and adjust accordingly.

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