Final gravity 1020 Why?

I'm a fairly experienced AG brewer. I use keggles and Beer Smith. My latest batch of "Session IPA (meaning not so heavy on the hops) was a normal brew with normal temps, especially mashing (150F for 75 min.) . I pitched Salfale 04 into one carboy and saved Nottingham into the other. My Notty was probably underpitched, but it fermented very well after a slow start. Both carboys had a beautiful, healthy krausen and seemed fine at 68F. The ferment slowed and flocculated sooner than expected. I roused the yeast and increased the temp for 36 hours to about 73F. Both carboys are now clear and pretty but the gravity is about 1020. OG was 1052. It tastes fine. Once I have a procedure worked out, I tend to try to repeat what has worked well in the past. Any ideas?

 

The final gravity measurement is with a hydrometer?

 

How long ago did you brew?

 

Yes with a new hydrometer that reads at 1.000 with water and I brewed last Sat. That will be day days in the fermenters in a couple of hours.

 

So same base beer into two different carboys with two different yeasts and both beers are sitting right around 1.020? Assuming it's been over a week and that both should have hit their FG by now I would say that two different yeasts bringing the same wort to the same FG would eliminate the yeast variable as being the likely culprit. After that id look at the recipe for too much unfermentable sugars, mash temp too high or thermometer being off, or fermentation temp getting too low causing the yeast to go dormant...but raising the temp and rousing them should get things kick started.

 

Sorry, this cracked me up.

I think we need a bit more information to help:

1) What's grain bill? Any extract used?
2) Did you rehydrate the 04? How many packs used?
3) By "saved Nottingham," do you mean it was harvested from another batch? How much did you use?
4) What size batch?

That does seem like fairly low attenuation for both strains, my first guess would be under pitching, and/or poor yeast health.

 

Yooper: 16.5# 2 row, 2#munich, 2# of various crystals malts a few ounces of black patent and roasted barley

My thermometer is pretty new and has been calibrated to ice water and boiling water. I also use a backup thermo everytime. I've had better luck with probe thermos than the floating dairy type.

Do you think that it is worth it to invest in a Blichman or other system to nail the consistency thing and make setup and cleanup easier?

 

My grain bill is on another post. No extract. I pack of S-04 for 22 litres. Safale said 20-30 litres. Fresh yeast. No rehydration per instructions and I have used this yeast several times before. No temp variation- my closet is very stable. The Notty was calced after the fact. It probably had 200-300 billion cells. Total batch about 11.5 gal. The OG exceeded Beer Smith's predicted OG from 1048 to 1052.

 

If you want to upgrade go for it. But unless this is a consistent problem (it doesn't sound like it is), I wouldn't think it's necessary to throw all sorts of money at it based on one data point.

 

Do you normally get that low with that much specialty malt? My barleywine finished at 1.026 with about the same amount of crystal (C15)

 

OT: "Session" means low ABV, not low hops.

Are you measuring gravity with a hydrometer or a refractometer? I don't blame the yeast, I think it's more likely the recipe and/or mash temperature (assuming no extract was used in the recipe). Did the recipe include any pure corn sugar to encourage drying it out?

 

They are different beasts due to OG. He's only got 2 lbs of crystal into a 20.5ish lbs grain bill. That's 9 or 10%. Not an insane amount.

A drop from 1.052 to 1.020 is only 60% apparent attenuation. Which is probably significantly less attenuation than your barleywine.

 

Not sure how I missed that low OG and the fact that it was a ~10gallon batch with that grainbill. For some reason I thought it was 5 gallons, which would make a pretty big beer.

 

A thermo can be on at freezing and boiling while off at mash temps. I would get a NIST traceable thermometer (readily available on Amazon for under $20) and check yours at mash temp.

No need to buy Blichmann for consistency, I used a cooler for a decade and was able to maintain perfect mash temps, just gotta trust the strike water math and know your system.