Attenuation, unfermentables and boil time

I have a beer with following fermentables:

6 pounds pilsen
5 pounds munich
1# carapils
.25 pounds chocolate
rogue pacman yeast

This was 7 gallon batch

OG = 1.045
mashed at 150 for 60 minutes.


I WAY overshot my water evaporation rates, I started with 9 gallons and ended up boiling for 120 minutes just to get down to 7 gallons.

I am wondering if the long boil somehow increased the amount of unfermentables in my wort? I have had the pacman yeast fermenting at 60 degrees for 6 days and I am only down to 1.022. I was hoping to end this thing at 1.012 or so.......

Did I mess up my fermentables with a lengthy boil carmelizing too many sugars? I am thinking about increasing the temperature, rousing the yeast and possibly adding a pound of dextrose to get things moving.

suggestions?

1.045 to 1.022 = not good beer

It's not because of a slightly longer boil. And there's no reason that grain bill should finish high.

How much yeast? How old was the yeast? Did you make a starter?

You might consider doing Fast Ferment Tests. I always do them just as a matter of course. I always have a little bit of leftover wort in the bottom of the kettle so I just take some of it and put it in a sanitized half-pint mason jar. Then I overpitch it (it doesn't need much) and put it on the stirplate (yes, that little mason jar actually works great on my stirplate). This way you'll know the reason a brew is finishing high.

SpanishCastleAle said:

It's not because of a slightly longer boil. And there's no reason that grain bill should finish high.

How much yeast? How old was the yeast? Did you make a starter?

You might consider doing Fast Ferment Tests. I always do them just as a matter of course. I always have a little bit of leftover wort in the bottom of the kettle so I just take some of it and put it in a sanitized half-pint mason jar. Then I overpitch it (it doesn't need much) and put it on the stirplate (yes, that little mason jar actually works great on my stirplate). This way you'll know the reason a brew is finishing high.

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I used a 1 liter starter of yeast that I cultered from a bottle. The ambient fermentation temp was in the upper fifties and the fermenter temperature was right at around 60. It appears to me as if I may have slightly underpitched, and that the yeast dropped out early because of low temps as well.

I opened up the fermenter, stirred everything up and raised the temp of the fermenter up to 67 over the course of last night and now I am getting a ton of activity and krausen has formed once again on the surface of the beer.

I thought pacman was good at cold temps, but aparently you are walking a fine line before it may drop out.

Yea, it sounds like it. I'm just guessing here but a 1L starter from such a small amount of yeast doesn't sound like nearly enough. But I just recently harvested yeast for the first time, from just one bottle of Bell's Pale Ale, so I'm not very experienced with this. I started with 12 oz. wort in the original bottle, then stepped it to .8L, then again to 1.7L. I just brewed with it this past Saturday but it appears to be fermenting normally and the FFT was nominal. Good to hear it started again.

SpanishCastleAle said:

Yea, it sounds like it. I'm just guessing here but a 1L starter from such a small amount of yeast doesn't sound like nearly enough. But I just recently harvested yeast for the first time, from just one bottle of Bell's Pale Ale, so I'm not very experienced with this. I started with 12 oz. wort in the original bottle, then stepped it to .8L, then again to 1.7L. I just brewed with it this past Saturday but it appears to be fermenting normally and the FFT was nominal. Good to hear it started again.

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I'll take a gravity reading here again tomorow, or whenever things start to settle down. But would think at 67-68 degrees pacman wouldn't take too long to finish the last 10 points or so.

The sad thing is, that I brewed this beer basically just to generate a nice yeast cake that I could pitch a double IPA on. Now I am having a few second thoughts about the viability of this yeast.

Do you think that if this beer finishes OK, even if I underpitched, that the yeast cake would be ready for a 1.085 maltose bomb!?

Yes, it should work out just fine for the next batch. You underpitched, and at a cool temperature, so that's why this batch is sluggish. It'll finish, probably at 1.010 or so (or quite possibly, even lower)! The yeast cake should be fine to use for your next batch.

YooperBrew said:

Yes, it should work out just fine for the next batch. You underpitched, and at a cool temperature, so that's why this batch is sluggish. It'll finish, probably at 1.010 or so (or quite possibly, even lower)! The yeast cake should be fine to use for your next batch.

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Nice! Thanks. I am still kind of new at this, under 20 batches total...


So it appears as if I did the right thing? Move to warmer temps and rouse the yeast?

****Note to self, next time I culture yeast from a bottle, step it up 2-3 times to ensure a nice pitching rate*****

I checked the gravity after 24 hours since reaeration and temp increase. Although I have a ton of airlock activity and krausen, I am not seeing a discernable decrease in gravity. I am wondering if I possibly just didn't get a good batch of yeast from the rogue bottle...or if I just need to relax and wait a week and check it again.

I wonder if the CO2 escaping and active fermenation possible makes hydrometer readings less accurate?

this morning I am down to 1.015 and still have krausen, looks like I woke the yeast up and they are going to town!