Low efficiency, now what?

[djonesax]

I usual don't have issues hitting my desired OG but last night I did three things different and got a 64% efficiency versus my usual 77%.

The first difference was that I wrapped the my converted Keg mash tun with a sleeping bag to hold the temperature better. Being that it was all wrapped up, I didn't stir it after the initial stir at dough in. It help its temp very well though from 153 to only 150. Where as before it would drop into the 140's over 75 minutes.

The second was that the first gallon of running had lots of grain in it, so I poured it back on top after the grain bed had settled. I don't know if that would cause an issue but its not something I have ever done before other than just a little bit.

I also, didn't mash out for 10 min at 168 this time.

Anyway, I was expecting 1.058 and got 1.048 which put my estimated ABV at about %4.43 and I wanted %5.7.

I'm wondering if I should just leave it alone, if I could add add some sugar, dme, or something to bring it up a bit. Right now, my intention is to leave it alone but thought I'd see what others do when this happens.

Thanks,

David

 

[janisco]

Do you mill your grain yourself? That's a big enough drop that the rollers might need to be adjusted and tightened up for a finer crush/better efficiency.

 

[blizz81]

If nothing else has changed in your process (esp as was mentioned, the crush width), and this recipe wasn't anything crazy compared to what you've brewed before, I would say the one thing out of those three that would possibly impact efficiency would be stirring, and then I would think it would really only be a problem if you had dough balls at dough-in / don't get a very thorough stir on your dough-in.

 

[johngaltsmotor]

Not stirring could have a big effect. You want to make sure the sugars are in the solution, not stuck to the grains and husks. I ready someone recently state that they started stirring every 15minutes and before lautering and picked up 5 or 10% over no-touch mashing.
The temp drop wouldn't have changed the efficiency much. It might change the fermentability, but not the efficiency.
Mash-out is similar. Getting it warmer makes sugars more soluble so they rinse off easier, but a big reason for it is denaturing the enzymes so they quit changing the type of the sugars that are already dissolved.
If you're big on ABV then adjust it. If you were looking forward to the flavor of this recipe then leave it.
I typically measure my pre-boil gravity so I can decide if I want to extend my boil to counteract a low gravity. I used to calculate how much light DME to add to get back to desired gravity but decided I'll forgo an extra 1/2gal if I'm really interested in hitting OG.

 

[Stauffbier]

Not stirring and not doing your typical mash out are both possible reasons for the change. Stirring helps facilitate conversion, and the mash out may have been helping the sugars rinse out of the grain for you in the past. Insulating the kettle isn't going to hurt anything. I would go back to your old routine, if I were you, but keep insulating the kettle.

 

[djonesax]

Do you mill your grain yourself? That's a big enough drop that the rollers might need to be adjusted and tightened up for a finer crush/better efficiency.

no the store milled it for me.

 

[djonesax]

Thanks, I have been doing the same recipe for the past 4 brews, changing little thinks to see the differences. Next time I will stir at least a couple time and add the mash out back in.

I also like the idea of adjusting the boil time based on the gravity of the preboiled wort. This recipe had a lot of pilsner malt in it though so I wanted a 90 minute boil.

David