Mash Efficiency Help

Wed Feb 19, 2020 12:50 pm

Hey Gang

Hi Gang, I'm hoping someone can help me understand whats happening in my brew. I'm a pretty detail lax all grain brewer, and I've run across an issue i can't figure out.

I've been working on this recipe.

The the predicted mash gravity is 1.070 but I've been getting a 1.046 from my mashes. I use a refractometer to measure gravity, and I made sure to re calibrate it on my second attempt, as my first got me close to the same results.

I use a Colman marine cooler as a mash tun, if that matters.

I aim for 12 gallons of pre-boil wort, and do a single infusion mash where I strike with 9 gallons of water and sparge with 8 which has gotten me the desired wort for my boil, but super weak from what I was expecting.

Can anyone point me in the right direction? I'm not sure what I'm doing incorrectly.

I am not a copycat nor from aus
Posts: 4
Joined: Tue Apr 11, 2006 9:24 am

Re: Mash Efficiency Help

Thu Feb 20, 2020 5:25 pm

Hi! I'm the only person who still comes here. Fortunately you're in luck and I can help you. Several things:

1) Your mash pH is too high at 5.7-5.8 unless you're treating somehow to bring it down. If not treating pH, that's going to hurt your efficiency in a big way. Add some acid (phosphoric, lactic, citric, vinegar, take your pick) and aim for closer to 5.4 as measured at room temperature, or 5.15 as measured at mash temp.

2) Volume measurements are key. If you're only collecting 12 gallons pre-boil, well... Brewer's Friend isn't right about this. You really want to collect at least 13 gallons, maybe even 13.5 gallons, and boil for as long as it takes to get down to 10.5-11 gallons. If your fermenters can't handle that much wort, then I guess start with 12 like you are. But collecting less wort also means collecting less sugar, so the efficiency falls as a result.

3) Striking with 9 gallons and sparging with 8 gallons also hurts your efficiency a bit as compared with the recommended 10 gallons strike 7 gallons sparge. With this, also, IF you are batch sparging, be sure to collect every drop of first runnings before adding the sparge water. This will maximize efficiency. IF on the other hand you are fly sparging, nevermind, except you should acidify your sparge water a bit then. With batch sparging, pH isn't important, but fly sparging it is.

4) It's an IPA, and with all the hops in there, you're going to lose some volume of wort which reduces efficiency a bit as well.

5) Finally, how's your crush? Do you mill the grains yourself, or does somebody else do it for you? LHBS's are notoriously HORRIBLE at crushing malts. Well crushed malt should have quite a lot of flour in it, with each kernel broken into 6-8 pieces. IF not crushed to that extent, well, start crushing it to that extent, then your efficiency will increase by about 10% on your next batch brewed that way. This should be number (1) above, but I'm too lazy to move it now. :D

All in all, any wort you lose is sugar lost which is efficiency loss. Make sure you minimize dead space and collect all your wort. Don't let any go to waste at the bottom of the mash tun. That's how I improved efficiency over time, learned to do all that.

Along with (2) above.... you could also increase efficiency if you were to extend the boil to say 90 minutes, 2 hours, 3 hours, whatever, by sparging a lot more than 7-8 gallons but maybe go 9-10 gallons and thus collect much more sugars and just boil off all the extra water. That's another option.

So..... just a few ideas. If I can be of further assistance, let me know, I'll be here every couple days to monitor the complete lack of traffic. Cheers, good luck, happy brewing.


"This is grain, which any fool can eat, but for which the Lord intended a more divine means of consumption. Let us give praise to our Maker, and glory to His bounty, by learning about... BEER!" - Friar Tuck (Robin Hood - Prince of Thieves)
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Re: Mash Efficiency Help

Wed Feb 26, 2020 8:18 am

Thank you so much for your help, Ill try implementing your suggestions next batch!

MUCH appreciated!
I am not a copycat nor from aus
Posts: 4
Joined: Tue Apr 11, 2006 9:24 am

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