Bonde

Recipes 

Attenuation with S-05

I had a few beers going quite low recently. I know the first thing that spring to mind is an infection here in the summer time but I very much doubt it due to my process and the looks/taste of it.

But, the last supposed to be, session Centennial IPA went from 1053 to 1006in 5 days (today). I’ve never seen that before and I’ve been quite hysteric about cleanliness recently due to a few very low fgs. No sign of infection though.

Is a thin mash really capable of making the worth that much more fermentable? 88%.

Mashed 1:5.5 so quite thin.

Obliviousbrew

Recipes 

More than the thin mash I´ll check on you mash temp, if temp is very low or you do a long protein rest for a long time with well modified malts you can get this, US-05 is a working horse too, some people have reported a low FG with it, I´ve used quite a lot and never had those problems, did you checked that you hydrometer is accurate?

Bonde

Recipes 

Had 2 thermometers going due to the recent problems with low fg. And even crosschecked them before brewing with 2 other thermometers.
Single infusion mashed at 68-69c (154-156) for aprox 2 hours incl. sparge (mashed 65) Also another crazy thing 11% crystal, that really speaks aginst the low fg.

HollisBT

Recipes 

A thinner mash will make a more fermentable wort, but like above, I think you might look more into your mash temps and also tell us your grain bill.


88% AA is pretty astonishing though.

duboman

Recipes 

+1 on mash temp, if you were below 150 you got a much more ferment-able wort and greater attenuation. Is your thermometer calibrated? You may be mashing much lower than you think Also, at what temperature are you fermenting at, high temperatures will cause fast and furious fermentations as well as off flavor production depending on the yeast.

Edit: WOW, two posts before I finished typing!

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Bonde

Recipes 

Grain bill:

Pale 66%
Crystal 120 11%
Munich 11%
Flaked Oats 11%

In terms of thermometers, I must admit that I do not use state of the art thermos. But 4-5 cheap digital ones. Threw 2 away as they were 2c off. Chose the one in the middle of them all, and hoped for the best, maybe not that good after all.

Fermentation temps are at a steady controlled 67.1f

weirdboy

Recipes 

I have (deliberately) gotten over 90% attenuation with US-05.

A 2 hour mash is pretty long, and likely to result in a more fermentable wort. If your thermometers are off by a degree or two, you are more likely to favor beta amylase and break down those complex sugars a bit more than you may have expected.

Bonde

Recipes 

Above 90% now thats crazy...

i thought i was crazy when my french Saison hit the late 90'ies... but us05...

The 2 hours was including batch sparge, the normal mash took 65min.

jtejedor

Recipes 

I would check thermometer as others have stated. I used to get crazy attenuation but now that I am using a thermopen my numbers are more in line with what they should be. That is a pretty thin mash though. I even do overnight mash and my attenuation numbers are still pretty close.

Denny

Recipes 

Waidaminnit....are you saying you batch sparged for an hour?

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