Would you dump?
Hi there, fellow brewers!
I recently brewed an imperial oatmeal stout @ OG 1.080. Mashed at 68°C (I guess that was my first mistake) pitched it on Windsor (second mistake) slurry from my previous brew (a robust porter). I aerated for about one hour and fermented @ 22°C. It took off like a rocket and then just died after less than 24 hours, no more life, other than the rare,occational burp. So I took a gravity sample, expecting something like 1.060, but it had dropped down to 1.032. In such a short time!!!??? However, three days subsequent readings show no mercy, fermentation has stopped for real. I detect no off flavours, but it is very fruity and way too sweet. Why couldn't it have just continued... So at this stage I'm considering to just count my losses, dump it and start over, i.e. lower mash temp and use a better workhorse for yeast. What would you do in my situation? Can I mask sweetness successfully? Or if I repitch another yeast, would I not still end up with something just as amateurish as leaving it sweet?
Thanks for input,
That 1.080 OG might've made too much alcohol for the yeast to tolerate. It'd just give up when it's tolerance level is reached. Might need a yeast that can take 12% or more to finish it.
I would try to restart..
It might be done. Oatmeal stouts generally have a lot of unfermentables and mashing a little higher would also create more unfermentables Although 154 is about right for an oatmeal stout.. I've had oatmeal stouts stop at 1.025(OG 1.060). Can you post your recipe and we can look at it.
Of course. Here's the recipe, along with all my notes so far. Thanks for your time.
Style: Imperial Stout
Batch size: 17.0 l
Boil volume: 27.0 l
Bitterness (IBU): 96.0
Color (SRM): 33.8
5.00 kg Maris Otter Malt, 76.9%
0.45 kg Flaked Oats, toasted, 6.9%
0.40 kg Crystal 50-60L (British), 6.2%
0.40 kg Crystal 40L, 6.2%
0.15 kg Chocolate Malt (British), 2.3%
0.10 kg Black Barley, 1.5%
50.00 g First Gold (AA 8.3%, Pellet) 60 min, 56.2 IBU
70.00 g Styrian Golding (AA 5.2%, Whole) 30 min, 34.1 IBU
50.00 g Fuggles (AA 4.2%, Pellet) 5 min, 5.7 IBU
Coffe, Coursely ground, 1.0 unit(s), Flavor 200 gram ground coffee. Make a strong filter coffee with 50 cl water, cool and add to secondary fermentation.
Danstar Windsor, 2.0 unit(s), Yeast I pitched on slurry from a previous brew. Otherwise, use two 11g.packets of yeast (total 22 grams).
Irish Moss, 1.0 unit(s), Fining , boil 15 min
How to toast flaked oats (havregryn) in your oven: On a cookie sheet, spread out and toast 500g. (yes, start out with 500g.) flaked oats in oven at 160°C for 90 minutes, turning the oats around and re-spreading them every 15 minutes, increase temperature to 180°C the last 15 minutes. I used 2 trays with cookie sheets in the oven with convection fan turning. When your kitchen starts smelling like a cookie factory, you know you're on the right track, and you can relax with a homebrew. Water will evaporate from the oats during the toasting, and you'll be left with about 450 grams, toasted, brown oats at the end, and as miraculous as it may sound, that's exactly what you need for this recipe. Now how cool is that! Store it dry and high for brewday, and toss it in the mash with the rest of your grain bill. Mash at 67°C for about 90 minutes. Boil 90 minutes, and follow the hop schedule. Add irish moss at 15 minutes as you hook up your wort chiller.
Brewday, 11 aug. 2012. Mashed at 68°C with 21 liters water, mash tun full with those quantities. After first run-off added 11.5 liters at 95°C, made 78°C in mash tun. Collected 27 liters, way too much. Cut back water. Boiled vigorously until about 22 liters (1hour), then added bittering hops. Collected 17 liters in fermenter, OG=1.080, too low.= 65% efficiency. Pitched on Windsor slurry from porter, Aerating with pump for about 1 hour. Fermentation started after about 6 hours and fermented vigorously for about 20 hours, then it slowed down, 24 hour later, no more activity. 13 august, about 42 hours after ferment start, SG=1.032. Hopefully it will go down some more. Next time, such high gravity brew needs lower mash temp, and use high attenuation yeast strain, such as nottingham.
Not a chance I would dump that. Nothing wrong with the temp you mashed at, just a stuck fermentation.
Maybe make a starter with Nottingham and pitch?
Thanks, I'd like to tell you *WOW* in about 30 days. Do you believe sg will sink when it hasn't moved at all in 4 days now? Or do you mean the sweetness will not be that cloying after 30 days?
RM-MN, Good eye! Yeastforbrains..., For a heavy brew like that you gotta wait 3-4+ weeks in the primary! Then bottle and wait some more. Patience, mon ami.
The initial period of fermentation proceeds rather quickly, then slows down and mellows out. The yeasts are taking their time cleaning up after themselves. Stouts and other heavy brews may take months+ to fully "ripen".
Like I said,you could try swirling the yeasty back into suspension to get it going again. But no splashing o2 is bad at this point. If that fails,then pitch the notty. It could even be you underpitched.
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