Mash Tun Efficiency?

[Acaciadrian]

Hey all,
I have recently see a drop of about 10% in my Mash efficiency. In the past I would consistently hit around 73% but in the last to brews that I have done I am right around that 62-63 range. I am using the same 10 gallon igloo cooler with a 5 in. stainless filter attached on the inside. My local HomeBrew shop did recently move and get a new mill but the owner has told me that he calibrated it to the same gap as the previous mill (even if it is slightly wider I didn’t think it could cause that big of a drop). My water/grist ratio has been 1/1.3 to 1/1.5 as usual. Any ideas on what could be going on?
I am fine adjusting my grain bill for this but just thought I’d throw it out there in case someone else has had a similar issue

 

[beermanpete]

The crush of the grain is certainly a likely cause of your efficiency drop. Water quality is a factor. Have you changed your water source? What about mash temp? Did you change your thermometer? You should check its calibration.

 

[day_trippr]

If the testimony is the only thing that has changed is the LHBS grain mill then that's gotta be the root cause of the efficiency drop.
It's really that simple...

Cheers!

 

[Acaciadrian]

If the testimony is the only thing that has changed is the LHBS grain mill then that's gotta be the root cause of the efficiency drop.
It's really that simple...

Cheers!

Thanks! I will chat with him next time I’m in there and run some citizen science maybe and do the same brew and see what the difference may be. I never would have expected that big of a drop though!

 

[day_trippr]

10% is actually a rather minor loss compared to some of the horror stories I've read here when a mill gap slipped without anyone noticing...

Cheers!

[edit] You could post a couple of well-taken pics of the next crush. If it looks broke we'll spot it

 

[Acaciadrian]

Wow I had no idea! Thanks for the help!

 

[doug293cz]

If the change in crush is the issue, then that means your conversion efficiency (percent of the available starch that got converted to sugar) has gone down significantly. You can measure your conversion efficiency directly using the method here. If your conversion efficiency is less than 90% then you need to worry about it. With a good crush, long enough mash time, temps good, and pH within range, you should easily get 95%, or better, conversion efficiency. Below is a table equivalent to the one at the linked reference, but with "round" qt/lb mash thicknesses.

Brew on

 

[Acaciadrian]

If the change in crush is the issue, then that means your conversion efficiency (percent of the available starch that got converted to sugar) has gone down significantly. You can measure your conversion efficiency directly using the method here. If your conversion efficiency is less than 90% then you need to worry about it. With a good crush, long enough mash time, temps good, and pH within range, you should easily get 95%, or better, conversion efficiency. Below is a table equivalent to the one at the linked reference, but with "round" qt/lb mash thicknesses.

Brew on

View attachment 569208

Thanks! That is wonderful! I sense something is off with my equipment(tun/thermometer/hydrometer) because my expected SG on the last batch was 1.078 and I hit 1.060. The SG was calculated in BeerSmith so pretty reliable source. PH was 5.4 and my thermometer(in question) read 150 start to finish