Imperial Stout Question

Hello all,

I'm new and on my 3rd partial mash brew. Here are the specifics:

OG: 1.084
Yeast: WLP007 (liquid, no starter, pitched at 4pm 10/12/09)
Temp at pitching: 70
Aeration: aggressive pour/splashing on wort and water
Temp for fermentation: 76-78 (no temp. control yet)

Do you think my yeast will get the job done? or should I prepare to pitch a starter?

1. Make a starter. Its not hard, you just need to make some wort with DME (100 grams per liter of water) and pitch your yeast into it about 18 hours before you need to pitch into the fermentor. I would do 2 liters at least (growlers are handy as are 2 liter soda bottles). Shake it as often as you can. You want some gas transfer (oxygen in, carbon dioxide out) so covering it with aluminum foil is not only fine but preferable to an airlock.

2. If you ferment a bigger beer like this at an ambient 78 the temperature will probably peak in the mid 80s and you will get a lot of higher alcohols (hot, solvent like) and probably more esters than you would want. This might be a good time to experiment with some sort of swamp cooler (wet towel +fan) or a water bath with some frozen soda bottles to swap out.

Thanks for the quick reply.

1. Are you suggesting that I pitch a starter for this brew or was that for future reference?
2. I'll get to work on a water bath.

You need a starter for that beer. Whether or not it will ferment successfully without is up in the air, but you can increase your odds substantially by making at least a 1L starter. 2L+ would be preferable.

Also, if you can find a way to keep it 70 F or below, do it. 76-78 is high to begin with, and once fermentation gets going, the exothermic process will likely cause the temp to exceed 85 F, causing you to wait many more months of conditioning before the beer is even drinkable. The wet t-shirt trick can work well if you are diligent about keeping it wet.

A starter would be a good idea. You can draw off a pint of the wort and cut it with an equal amount of water. Keep it warm and you can dump it back in in 48 hours.

david_42 said:

A starter would be a good idea. You can draw off a pint of the wort and cut it with an equal amount of water. Keep it warm and you can dump it back in in 48 hours.

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Interesting. I sort of had the same question. I brewed a pretty simple 1.056 APA yesterday and just tossed in a vial of WLP008. I normally make a starter but for some reason or another I just forgot to this time. Would you suggest pulling off a pint as you mentioned above? If so, whats the procedure? Just pull it off, mix with water and wait? Or do I add more yeast to the "starter"?


Not trying to hijack the OP. Just thought I could piggyback.

Thanks for the tips! Is there anything else that I might be overlooking or that I should pay special attention to with a "big" brew?

Definitely cool the fermentation as quickly as possible. With ambient air at 78 degrees, your wort may be cranking away at 85, which is way too high. Put it in a water bath with ice bottles if you have to.

High gravity worts stress the yeasties to the max. Tossing in a re-hydrated sachet of dried ale yeast wouldn't be out of the question, IMO. Most of the off flavors are produced in the beginning phases of fermentation.

Flounder said:

Interesting. I sort of had the same question. I brewed a pretty simple 1.056 APA yesterday and just tossed in a vial of WLP008. I normally make a starter but for some reason or another I just forgot to this time. Would you suggest pulling off a pint as you mentioned above? If so, whats the procedure? Just pull it off, mix with water and wait? Or do I add more yeast to the "starter"?


Not trying to hijack the OP. Just thought I could piggyback.

Click to expand...

No problem, I'd like to hear the answer to your question as well.

Without a starter, especially in that big of a beer, you can expect the following:

1. Underattenuation (i.e., stuck fermentation).

2. Strong esters.

3. Diacetyl.

You could also get fusel alcohols, acetaldehyde, and maybe even some minor autolysis. WLP007 is a great yeast for high-gravity ales, but it's not made of magic. You can see how it goes and, if you need to, repitch a starter or some dry yeast to finish it up. No matter what, you probably will not get the beer you wanted unless you pitch a good starter in the first place.


TL

Update: Fermentation has begun and seems just as active as my previous low(er) gravity brews. Fermenter has been placed in a 60F water bath and a 2L starter is in the works.

david_42 said:

A starter would be a good idea. You can draw off a pint of the wort and cut it with an equal amount of water. Keep it warm and you can dump it back in in 48 hours.

Click to expand...

David, I'm curious as to why it needs to stay warm?

I ended up with a 1.030 after 9 days (target gravity of 1.018). It tastes good so I've added the whiskey-oak chips to the primary and will let it sit for another week.

I'm confused; did you make the starter for this batch or your next one?