Pliny the Elder Clone fermentation gone awry

I made a 2 gallon batch of PTE.
Recipe was:
4.6# American 2-row
0.2# crystal 40
0.25# cane sugar added w/10 minutes left in boil

hops:
1.35 oz columbus @ 90 min
0.25 oz centenial @ 45 min
0.33 oz simcoe @ 30 min
0.33 oz centenial at flameout plus 10 min
0.83 oz simcoe at flameout plus 10 min

dry hopping today w/0.5 oz centenial, 0.5 oz columbus, 0.5 oz simcoe for ~ 5 days.


I did single batch sparge BIAB. Mashed at 151 degrees for 75 minutes in kitchenmaid cooler. Mashed w/1.5 qrts water per pound. Starting boil volume was ~3.5 gallons. Did a 90 minute boil. This was first time using new Edelmetal burner so final volume was low at ~1.75 gallons so chilled to ~68 degrees and added 1 qrt water to make 2 gallons for fermenter. O.G. after volume adjustment was 1.073, target was 1.072. s'ok.

Fermented with BRY 97 yeast. Temp in my insulated fermentation box is ~68 degrees +/- 2 degrees using seed mat and thermostat.

After 2 days gravity was 1.061. s'ok. At 6 days poured small taste sample that was very foamy, actively fermenting. Kinda unusual to be foamy 6 days in. Tasted fine. At 11 days, I measured gravity to be 1.005. not foamy, tasted, smelled fine. Target final gravity from brewmate was 1.014. Why such a low gravity?

Only thing I can think is that I actually mashed at a temperature way lower than what I measured and got more fermentables than expected. I use a glass thermometer. Stir the mash with a paddle, insert thermometer. Not rocket science.

What's this going to taste like? I haven't used BRY 97 before so I don't know if that is a factor in the low gravity.

You may have just had a temperature slide during the long mash from 151F down into the mid-140s - or you thermometer is not highly precise and reads high. Either of these would account for a much higher fermentable wort and a much lower FG. Being almost completely highly modified base malt and table sugar, it's no wonder you hit such a low FG. I use a highly precise digital thermometer and I can tell you than my old glass brewing thermometer reads about 4F higher than my digital. If yours is the same, then you effectively mashed at 147F which would totally explain the low FG.

Regardless, I would not worry about the outcome of the beer. It's still going to be a super-hoppy IIPA. Maybe a little less body than expected but otherwise about the same as you would have got at a higher FG. After checking your thermometer and adjusting your process accordingly, brew it again at the correct mash temp and see the difference for yourself.

I made another batch of beer yesterday. Used calculator to calc dough in temp for 8.9 lbs grain and 1.5 qrts water/pound, yada yada. Let strike water sit in cooler until hit dough in temp. Measured doughin temp v. carefully and nailed that at 166 degrees. Measured mash temp after adding grain to strike water v. carefully, it was 4 degrees low at 150 degrees. hmm. Only thing I did NOT measure was grain temperature before adding strike water. I just assumed it was 68 degrees because that is what the house temp is.

It was not. It was 64 degrees in the grain bag in my office. Not sure how that's possible since room temperature was 68 degrees. But whatever, it wasn't. So, will measure grain temp from now on and adjust dough in temp as needed.

Duooh!

Good info!! I'm glad you were able to determine one potential spot for temp losses. Grain temp is something I generally take for granted and assume it's in the 68-70F range too. Guess I need to keep that aspect in mind from now on.

Was the bad of grain leaning against an exterior wall? That would lead to heat loss and lower temp.

Another possibility would be programmable thermostat. If your house lowers to 64 or some such at night, it would take a while for a solid bag of grain to warm up.

I've had to adjust temps from time to time. Drain off some wort and heat it up, then add it back in.