Efficiency issues and mash thickness

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Hydrometer Jar
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Joined: Thu Nov 07, 2013 4:38 pm

Efficiency issues and mash thickness

Post by frontporch » Mon Aug 25, 2014 4:40 pm

Find I’m having some efficiency issues when targeting SG post-boil batching. I just did a Belgian Strong golden with 25# Briess 5301 PaleAle, 1.5#CaraPils, and 1# Vienna. Mashed at 144 for 30, 160 for 30, with a 168 mash-out and a 170 fly-sparge with 2.5G. I made 2 - 10G batches: The first, I used a water/grist ratio of around 1.8qt/lb. The second, I used between 1.4 and 1.5qt/lb. Interestingly enough, my pre-boil gravities matched at 1.042, but varied wildly post-boil (1.067, 1.057). My target was 1.080. As a quick primer, I’ve included Palmer’s rough-out:

From Palmer's How to Brew, some other considerations beyond efficiency:

         "The grist/water ratio is another factor influencing the performance of the mash. A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars. A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer. A thicker mash is more gentle to the enzymes because of the lower heat capacity of grain compared to water. A thick mash is better for multirest mashes because the enzymes are not denatured as quickly by a rise in temperature."

Also wondering if any of you have found engaging the recirculation all/part/variations during the mash has aided/hindered you in hitting your target efficiencies.

I’d appreciate any thoughts any of you might have - happy brewing!

Pint Glass
Posts: 65
Joined: Sun Jan 19, 2014 6:56 pm

Re: Efficiency issues and mash thickness

Post by mchrispen » Wed Aug 27, 2014 5:00 pm

Not sure where to start on help, but here is a shot:

1.) Split extraction efficiency from brew house efficiency. I find it is easier to look at extraction without dealing with all of the system losses, etc.
2.) How is your crush? I have had to find a happy medium from my former very fine crush to the right one for the system. The folks at Sabco recommend a fairly course crush to ensure good recirculation and lautering. They put the right target around 0.045" - however you should crush to (a) leave the husks mostly intact while (b) thoroughly crushing the endosperm. I crush most of my base malts right now at 0.04". Any finer and I get concerned about gumming up the pump or the heat exchanger... and keep rice hulls handy.
3.) How is your mash pH? With high or low alkalinity water, you could have issues with pH and enzyme activity.
4.) Have you calibrated your volumes recently? what are your planned system losses in the tun, and chiller? Most of my efficiency issues related to post mash are volume errors - too much sparge water, not enough boil off, etc.

From what I observe, mash thickness affects the speed of conversion. Thicker mash converts faster, but still within the ranges you are talking about - 1.25 -1.5 yields about the same. Thinner mashes seem to require much longer mash period for conversion, and I suspect there is a temperature variable in play as well.
Matt Chrispen
http://www.accidentalis.com - blog

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