Losing heat in the mash = poorer efficiency?

[Judochop]

Take this scenario for example: if mash-in begins @ 154, and drops to 150 over the course of 60 min.

I use this particular example because it happened to me (as far as I can know with the instruments I use) and my efficiency was not as good as I had been seeing in previous batches using the same mill from the same LBHS (which I can only trust is a constant here) and the same process.

And now my attempt to make theoretical sense of this. At 154, beta-amylase are becoming slowly denatured, and the alphas are just barely getting started. Then the mash dips below 154 where the alphas are no longer working much at all, and the betas are now a bit the worse-for-wear from sitting at 154 for a period of time. The result: less overall conversion than I’d have seen if I had held my temperature.

Would some knowledgeable folk here be able to confirm or refute this?

If a loss in conversion/efficiency is not the primary concern when the mash temp drops, then what is there to be concerned about?

tanx
-jc

 

[bumstigedy]

That seems to make sense to me. Since I have switched to a direct fire mash and now maintain a more constant temperature during the mash my efficiency has increased. Not sure that is the sole cause of the efficiency as I also started recirculating and switched from a cooler mash run to a boilermaker.

 

[astropunk]

Excellent question, Ive wondered the same thing myself, and basically came to the same conclusion.

One time I overshot my mash temp, but went ahead with the mash anyway. I mashed at about 158-156 with a target of 152. The end result was a final gravity higher than the target gravity, which I have never had before. This made my efficiency look great, but actually resulted in sweeter, less fermentable beer.

 

[dcp27]

its certainly possible, although ive never experienced it. it varies system to system, but I'd expect within those constraints that you would have had full conversion tho, especially if you happen to mash out or batch sparge. guess the only way to know for sure is with a starch test.

id check out some of kai's stuff on efficiency if you haven't yet: http://braukaiser.com/wiki/index.php/Main_Page

 

[bannonb]

Not sure about efficiency affects. I'd think more about sparging and even mashout to impact that.

Like Astropunk talks about...higher temp conversions yield maltier/sweeter beer where lower temp conversions yield dryer/alcoholy beer. You will fully convert at any of those temps, so the only risk I see is loss of control over the desired body.

Stable mash temps appear to be the most important factor to me achieving my current quality plateau in brewing. Stable fermentation temps are in the top two with mash temp.

A year ago I built a RIMS system so I could recirculate the beer and keep the temp within a degree during the entire mash.

With that in mind, I think keeping temps consistent throughout the mash by stirring is a good idea and 4 degrees loss is not that big a deal.