Over attenuation

All of my beers are over attenuating. I brew all-grain via batch sparge. I just brewed an ESB using Wy1469. It's a lower attenuation strain and my resting sach temps were 152F. It should have finished at the 70% mark but it still attenuated to 78%.

It's been the same with all my batches the last couple of months. It's really frustrating because I want some sweeter beers but their all turning out thin with strong alcohol. It's really frustrating because I hit all my marks on this ESB and I was really expecting a fantastic beer.

The only thing I can think of are my protein rests. I started doing decoction mashes to increase extraction and maltiness. . . . it certainly increases extraction efficiency (I often hit 89%)! The protein rest was at 125F for about 45-min before I added the decoction back raising temps to 152F. What should I be doing differently?

If you are looking for a sweeter end result your best bet is to stop your fermentation at a higher gravity. If you don't want to sacrifice any alchohol content you will need to boost your malt bill accordingly. If you don't use brew software already you might want to consider trying some. It can help you make these adjustments without having to drink too many batches that are less than desireable.

If you want more body and less alchohol you could try to step up a few degrees during the last third to quarter of your mash schedule.

The first thing would be to check the calibration of your thermometer, you may be mashing at a lower temp than you think. If its not the thermometer I would suggest you start doing a mash out if you don't already. I was having a problem with over attenuation so I started mashing at a higher temp. Then when I started doing mash outs I noticed a big difference in attenuation, I was getting the same attenuation mashing at 151 with a mash out as I was mashing the same recipe at 156 without a mash out.

Just two pennies. Take with a grain a grain of salt..

Keep it simple. Forgo the protein rest. Do a single infusion batch sparge at "Your" thermometer’s reading of 155. Sparge with 190F water.

This should make less fermentable wort, reduce attenuation and increase body.

You could also throw in a little Crystal for added sweetness.

jmancuso said:

The first thing would be to check the calibration of your thermometer, you may be mashing at a lower temp than you think. If its not the thermometer I would suggest you start doing a mash out if you don't already. I was having a problem with over attenuation so I started mashing at a higher temp. Then when I started doing mash outs I noticed a big difference in attenuation, I was getting the same attenuation mashing at 151 with a mash out as I was mashing the same recipe at 156 without a mash out.

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This was exactly what I was thinking.

I was going to suggest just adding some unfermentable sugars. I was thinking some Lactose could do the trick. It will definitely make it a little sweeter. Good luck!

Thermometer may be the problem. I recently had to throw away my kitchen digital thermometer because it couldn't decide what temperature the wort is. I've also decided to rerun the recipe with a single infusion mash at 156F with a mash-out, let it ferment down and then blend it with the over attenuated batch. Hopefully, they will balance each other out enough to be enjoyable. The over attenuated batch is tasty, just way to alcoholic for a session beer. I've also noticed (recently) that when I add the infusion (or decoction), the temp goes up, but then it comes back down slowly??? For example; I add enough HLT water to bring mash temp to 156F, but over 10-min or so, the temp goes down to 152F. I speculate that there is some heat exchange going on between the grains and the water. I wasn't paying close attention to this at first, but now I'm constantly measuring mash temps. . . . thanks for the reply's everyone. Cheers!