Cedar Rapids Brewing Society

So I pretty much run a 70% efficiency brewhouse with a 5% variance either way. No matter what I change (processes, no equipment changes yet) I cannot seem to get my efficiency to consistently go up. I honestly don't see why I shouldn't be getting 75% pretty regularly. The only thing I can think of is the crush.

Here's my equipment:
-Schmidling MaltMill - non-adjustable (factory setting is .039")
-Igloo Ice Cube cooler with SS braid, 1/2" drain

Process:
-malt conditioning at least 10 min before crush, made no difference.
-mash-in - I have mashed in at anywhere from 1.25 qt/lb to 1.6 qt/lb all with similar results, stir vigorously for a few min, I used to stir at 30 min but that doesn't make a difference - last batch was mashed @ 152, still only 71%.
-mash out or no mash out, doesn't seem to make a difference.
-batch sparge - sparge once or with 2 equal batches, doesnt make a difference if I do one or two, stir vigorously for a min, let sparge sit for 10 min, drain

At this point I will take a pre-boil gravity and it is always lower than what I am expecting. This past batch it was about .002 points lower. Final OG was .003 points lower, at 1.050.

As I've mentioned above, I've changed up my processes quite a bit over the years. If I found one change that upped my efficiency, I would duplicate it a couple times but have never found any consistent increase.

The only thing getting a mill did for me was to get me more consistent at 70%. It dialed me in pretty much at that range but didn't raise my efficiency much if at all. Looking back I should have gotten an adjustable one, but maybe Santa will be nice this year. Other than the mill, anyone have any thoughts on this? Its something that frustrates me almost every brew.

Have you checked your thermometer? Maybe your mashing higher then you think. I noticed mine is off at boil (197) and I think my last couple beers have been too sweet. My efficiency has dropped as well.

I'm not sure what your crush looks like, but Rock Bottom did a test on crush vs efficiency and found a coarse crush was more efficient then a fine crush.

Have you considered efficiency as a function of sparge volume?

If you think about it from the perspective of some absurd limits, this relationship must exist. For example, if I sparge 1 cup of liquid, I will be extracting only a tiny fraction of the total available sugars. On the other hand, if I sparge 1000 gallons of liquid, I will probably have extracted almost all of the sugars. The relationship is undoubtedly asymptotic, where, for example, you might hit 80% efficiency at 8.5 gallons of sparge water, but only 95% if you go up to 20 gallons.

Kai Troester wrote an article about this for Batch Sparging. If you're fly sparging, I would imagine something similar is probably going to occur.

http://braukaiser.com/wiki/index.php/Ba ... g_Analysis

Tom, I should have mentioned that I have used a few different thermometers, and my past two have been calibrate-able, and am pretty sure they're spot on at this point. I have run into temperature issues in the past though.

Lee, in the not too distant past I did everything I could to do a 50/50 split between strike water and sparge water volumes. Lately I've been experimenting with a thinner mash, and then skipping a mashout and using the remainder for a single or double batch sparge. Unfortunately I did mostly all of the water volume calculations in scribbles on my printed out brewsheet, so I don't have any old data to compare to recipes and see where my efficiency was on a particular date. I would just figure out my evaporation rate through Beersmith or now Beer Tools Pro and then calculate my water volume from there, based on whether I was going to be concentrating on equalizing my strike/sparge water volumes or whether or not mash thickness was more important. I would do around 3 batches with a particular process and see that there were still inconsistencies, so I would try something else.

This is my crush without conditioning. I will take one with conditioning, maybe on some leftover Amber malt I've had sitting around for a hundred years...
https://picasaweb.google.com/1aaronsmit ... directlink

One really simple way to improve efficiency is to have less volume loss in your system like kettle dead space in your mashtun/and or brew kettle. For fly sparging, my efficiencies improved significantly when I really slowed down the sparge. This was also mentioned in a BN podcast where a bunch of brewpubs where messing with crush of the grain thinking the smaller the better. They found a less agressive crush and slow sparge provided consistent results. They said they were rushing the sparge so they could end the work day. Adding an hour for them provided the results they were looking for. My typical sparge is around an hour on a 10 gallon batch of beer. They also mentioned if you need to speed up the sparge, go slow at first and speed up towards the end.

I have been pretty busy this week and haven't had a chance to post any conditioned crush pics, and going out of town this weekend. I'm pretty good at getting as much as I can out of my mash tun. I have never tried to calculate dead space though. To do that I would need to know my grain absorption rate. How would I go about calculating that when both the absorption rate and the dead space in my mashtun are unknown?

I'm assuming the coarse crush=higher efficiency is for fly sparging systems? I would think that it wouldn't be that big of a factor in batch sparging since the mechanism of how the sugars are picked up by the water is different. Am I way off here?

The dead space I refer to is just the amount of fluid left in you kettle. For example, fill the mashtun with water, drain it through the ball valve. Then dump out what is left behind in the a measureable container.

Hmm, yeah I guess that would be an easier way!