To re-pitch or not to re-pitch??

ATOpro · Feb 1, 2016

I was shooting for a 7-8% coffee stout but ended up with only a 5%! My FG (which i took while transferring into secondary after 2 weeks in primary @ 66-68F) is 1.040 after an OG of 1.074! I added a extra pound of corn sugar to try to achieve that 7-8%. I used a big starter of harvested safale-05. I have read posts about re-pitching more yeast as being an option but couldn't find anyone that posted results if it worked. So does anyone have a reason not to re-pitch?

Also I have never used lactose or brewed a stout before, but after 2 weeks of being seal in my primary there was an intense sour alcohol smell when I opened the bucket. I thought for sure it was going to be above 7% because of how strong the smell was but nope. Everything looked perfect with no signs of infection. Is that normal? Any suggestions help, Thanks.

.5 lbs Chocolate Malt; Breiss info
.5 lbs Black Malt; Briess info
.5 lbs British Dark Crystal info
8.4 lbs CBW® Golden Light Liquid (Malt Extract); Briess info
2 oz Fuggle (Pellets, 4.75 %AA) boiled 60 min. info
Added at last 15 mins of boil:
1 lbs Corn Sugar info
1 lbs Lactose info
1 ea. Whirlfloc Tablets (Irish moss)
4 oz. Coffee (grounds)

dkennedy · Feb 2, 2016

How does it taste? If it tastes good, then my advice would be to drink it, and re-adjust next time...but I keg, so the concern for bottle bombs is nil.
I'll resist the urge to blame the corn sugar- that's more than I would care to use in a porter (I prefer malty porters anyways), but it shouldn't have caused a stall (might be contributing to flavor/aroma oddities though, especially if the 68 degrees was ambient temp at fermentation). If you weren't already in a secondary vessel then I'd suggest rousing the yeast bed and possibly warming it a bit to encourage cleanup.
If you can't keg it, or if it's cloying (which is quite possible), then I'd build a starter and repitch at peak growth- that should prepare your yeast for the alcoholic, low-oxygen, environment that you're about to toss them into. I'd expect 7% out of this, at best- quick math says that around 1.020 is probably your floor...that pound of lactose isn't going anywhere.

Good luck!
DK

MrFancyPlants · Feb 2, 2016

Go by taste as recommended, but since you have all that lactose in there, I think that this would be a good candidate for amylase or even beano to help bring the final gravity down some.

andy6026 · Feb 2, 2016

I haven't ever brewed that style, so take my advice cautiously:

A FG of 1.040 seems extremely high to me and I've never known US-05 to have a reputation for stalling out easily. This would lead me to first check your hydrometer to make sure it's working properly (test it in water to make sure you get 1.000). The paper measuring card inside may have gotten moved, which has happened to me before.

An infection, as far as I'm aware, would also lower your SG to below what you would expect - so I doubt that's the case too.

I would be very wary of bottling a beer with an FG that high. If the hydometer isn't giving you a false reading, then as the above posters have suggested, give the fermenter some gentle agitation to see if it can rouse the yeast back into action. If the problem persists then I would seriously consider re-pitching, unless someone comes along with significantly better advice.

ncbrewer · Feb 2, 2016

Are you using a hydrometer or refractometer?

Siberian · Feb 2, 2016

Warm it up a bit to 70-74 degrees, you are well past the growth phase and a bit warmer temp combined with shaking/rousing might help encourage the yeast to wake up and finish.

ATOpro · Feb 3, 2016

Thanks for all the suggestions!It does taste good. I let the sample from the hydrometer reading steep overnight in some slightly grounded up coffee beans in the fridge and it was great. I drank that instead of my usual cup of coffee. Anyway, I checked my hydrometer and it measures a 1 in water, which is a bummer. I have raised the temperature but no signs of any activity. So I will give it another week and take another reading. Just to weigh out my options, if it stays at 1.040 after rousing and raising the temperature, should I still be concerned about bottle bombs? I'm also checking into amylase just in case. Thanks again guys for your help.

madscientist451 · Feb 3, 2016

I'd pull a 1/2 gallon sample and pitch some Nottingham or similar English ale yeast,along with some yeast nutrient, but not the S-05. See if it kicks off, and if it gets going good, pitch the whole starter into your stout. I'd ferment in the low 60's and ramp it up at the end.