Low Mash Bad Efficiency

I was going to mash at 149, hit 147. left it there for 45 minutes, took 2 gallons, heated on the stove, poured back in and hit 154, left for 1/2 hour. I guess the low mash will give me better attenuation, but I had really bad efficiency - like 65% with 1/2 lb corn sugar added at the end of the boil. And I have been a pretty consistent 75 - 80% for many batches. Could my weird mash have anything to do with it?

doublehaul said:

I was going to mash at 149, hit 147. left it there for 45 minutes, took 2 gallons, heated on the stove, poured back in and hit 154, left for 1/2 hour. I guess the low mash will give me better attenuation, but I had really bad efficiency - like 65% with 1/2 lb corn sugar added at the end of the boil. And I have been a pretty consistent 75 - 80% for many batches. Could my weird mash have anything to do with it?

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Im assuming you pulled the thin part of the mash..did you bring the pulled decoction to a boil? or what temp did you heat it to? Usually when using this technique you pull the thick part of the mash so you allow the enzymes to continue to work in the MT..if you pull the liquid(thin) part you denature the enzymes..thats one idea..what was you OG cause high gravity mashes are always lower Efficiency..anyway i would not worry about it

ABVIBUSRM said:

Im assuming you pulled the thin part of the mash..did you bring the pulled decoction to a boil? or what temp did you heat it to? Usually when using this technique you pull the thick part of the mash so you allow the enzymes to continue to work in the MT..if you pull the liquid(thin) part you denature the enzymes..thats one idea..what was you OG cause high gravity mashes are always lower Efficiency..anyway i would not worry about it

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I heated it to nearly a boil - could see foam starting to form on top. I didn't measure the temp but it had to be around 200F. I batch sparge, so I'm not sure I understand but I basically did my lauter just like I'd be going into the boil kettle. I pulled 2 gallons, and there wasn't much left in the mash tun so I pulled nearly it all. I only ended up collecting about that much in my first runoff after leaving some in my pump hoses. Then I sparged with 5 gallons. Denatured the enzymes - had no idea. I thought it was a better idea than just adding some boiling water to bring my temp up but I guess not. I've done it once or twice before and never noticed such an efficiency hit.

so lesson learned - should have stuck with 147F for an hour? will this impact my attenuation?

If you mash too low not all of the starches will dissolve, which is why most people take it to 149-150 (and needs to be pretty stable there). That is actually the high temp for beta amylase range, but is needed because otherwise you don't get anything for beta to break down, since alpha is not there helping to dissolve the starches.

I think if you boiled some of the mash that actually helped dissolve the starches in that boil. I think you just got low eff. because of low starting temp. My advice next time, just start adjusting pretty soon after you check temp, so you're in the sweet spot.

I brewed basically this same grain bill once before, mashed at 152F hit 1.06 pre-boil which was 73%eff. I was trying to mash lower to attenuate more this time, and hit 1.05 pre-boil 67% eff. I guess not too terrible. I think I had a good plan targeting 149F - but I screwed it all up! And maybe learned something.... I have never done a real decoction - I do need to learn the mash chemistry better... Anyways, thanks for the help!

What you did is called a turbid mash. It's got lambic brewers do it. If you pulled nearly all the liquid portion and headed to near booking you denatured nearly all your enzymes. So you effectively did a 45 minute mark at 147 then a mash out. So you left s lot behind in the grain. It'll be a pretty fermentable wort as well.

morticaixavier said:

What you did is called a turbid mash. It's got lambic brewers do it. If you pulled nearly all the liquid portion and headed to near booking you denatured nearly all your enzymes. So you effectively did a 45 minute mark at 147 then a mash out. So you left s lot behind in the grain. It'll be a pretty fermentable wort as well.

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Interesting. I was thinking it was a good thing I let it ride for at least 45!

It is! As the temperature goes lower the reactions slow down so a 147 mash will take longer than a 157 one. When mashing low for a fermentable wort I like to leave it at least 90 minutes. Sometimes as long as two hours.

I brewed another low mash temp batch in the past where I did this same thing the first batch - pulled and warmed on the stove at around 30 minutes, but I don't think I warmed as much.

Anyways, I got 75% efficiency. I brewed that recipe again yesterday, mashed at 150F knowing it would drop quite a bit since it is cold here, and at an hour it was around 144F. I added some boiling water and brought it up to 147F, let sit for another half hour - did 2 168F sparges, and ended up getting 89% efficiency!