Attenuating too low

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shimbii

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Hey all,

I've recently started brewing all-grain and have about 4-5 batches under my belt. Everything has been working out well with my system with the exception of some of my brews seeing over 80% attenuation when I'm expecting 70-75%. I'm wondering if it is just the way my system is working and I might need to just mash a few degrees higher. Here are some details of recipes that went way lower than planned however they taste good just a little less body than I'm shooting for. I've been mashing for 60 minutes and stirring very well at dough in and another 3-4 times during the full 60 min mash. I'm doing a single infusion batch sparge at an initial ratio of 1.33 qt/lb. Lastly, I've calibrated my thermometers and they're giving true mash temp readings so I know I'm hitting the temps that I've recorded.

Magic Hat #9 clone:
- Mash settled at 154 after dough in and ended at 151 after 60 min.
- Used wyeast 1968 London ESB which is supposed to have ~69% attenuation... I pitched a 1L starter
- Fermented right at 68 degrees for two weeks
- OG 1.052
- FG 1.009 (I was expecting mid-teens but I got over 80% attentuation!)

My 60 minute clone:
- Same exact deal as above... mash settled at 154 after dough in and ended at 151 after 60 min
- Used wyeast 1187 Ringwood ale which is supposed to have ~70% attenuation - I pitched a 2L starter
-Fermented right at 68 degrees for two weeks then dry hopped for a week in secondary
- OG 1.061 (a little low due to low efficiency from bad crush)
- FG 1.011 (I was expecting mid/high-teens but got 81% attenuation again!)

Should I just try mashing higher on my next go-arounds?

Any advice would be appreciated... not sure if anyone has had similar experiences. Oh, I do want to note that my extract brews do seem to attenuate by the expected amount. This really leads me to believe my issue is somewhere in the mash.
 
At 151, you're mashing for very fermentable wort. If you mash at 154, you'll notice a bit less attenuation. Also, double check your thermometer- if it's off even 2 degrees, you could be mashing at 149!
 
Thx for the reply...

So I'm assuming that most of us who mash in a cooler mash tun end up losing a couple degrees during the duration of the mash. If you have a target mash temp of 154, are you shooting to hit 154 at the beginning of of the mash ending a little bit lower or are you intentionally hitting high to eventually end up at 154 at the end of the mash?

For me, I've tried to hit a degree or so above my target mash temp and then settle to a degree or two lower than target by the end.
 
In all reality, I think i'd answer my own question by trying to mash a few degrees higher in my next go around.
 
What I do is preheat my cooler with hot water. I'll usually add the water at about 180 degrees, and then let it drop to my strike temperature. Then, it seems like I don't lose more than one degree over the course of the mash. Preheating the cooler for at least 15 minutes seems to make a huge difference!
 
I have the same idea but use a little different method than Yooper. The bottomline, important point is that preheating the mash run makes a difference.

I loose very little (sometimes not even one degree) over an hour mash.
 
So go figure... all three of the thermometers that I have are off! I have two floating thermometers and one lab thermometer... and they're all off by 1-3 degrees which had me mashing lower than expected. Before, I assumed that the lab thermometer was spot on and the other two floating thermometers that I had were within 1 degree of my lab thermometer which I was using as a reference. I checked all of them together last night with my cdn probe thermometer that I usually use for BBQ and found that they're off. Yes, it sucks that I have two extremely "dry" beers on tap now but I'm glad that I think I found the issue and will try to fix it on my next batches. I'll call one of them my saison IPA.

I just ordered one of those digital pocket KM12 deals so I'm hoping it's more accurate. Thanks for all of the info.
 
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