High Gravity Fermentation...

[mozart4898]

So I haven't posted in a while...been brewing pretty regularly but just have been busy and haven't posted but I do read threads from time to time. Anyways, I've kinda started a tradition (only in it's 2nd year) of brewing a big beer on New Year's. Last year it was an imperial stout (OG 1.111), and this year I decided on a barley wine. Last year's brew required a pretty significant amount of DME to reach that OG. I intended to not use any DME at all for this one so I made sure I had plenty of grain (24.25 lb for a 5 gallon batch), planning on low efficiency but I hoped to still at least hit 1.100.

Well, long story short it turned out my efficiency was better than I'd planned (69.1%, not crazy high but 4-5% higher than expected). OG ended up 1.112. I had 2 packs of US-05 to pitch for this since from what I've read, few yeasts really seem to do better with high gravity whether dry or liquid. So I pitched those two buggers into this huge beer (rehydrated, of course...and with 2 Tbsp of yeast nutrient in the wort as well).

There are no crystal malts in this beer...23 lb of base malt, 1 lb of special roast, and 0.25 lb of chocolate, so I was expecting this to get to the high teens or around 1.020 for FG. I believe from my reading that US-05 will handle 12-12.5% ABV but what I'm most concerned with is how to carbonate this sucker. Tried champagne yeast with the imperial stout last year and it pretty much failed, and that one finished at 1.029. Suggestions on how to get this one to finish/carbonate?

 

[cjgenever]

Wlp099 high gravity yeast. white labs claims It's good up to 25%.

 

[mozart4898]

I thought about the 099. Never used White Labs yeast cause no store I've been to carries it (would have to order it online). Would it need a starter as if it was being used for primary fermentation? It'd seem kinda extreme to dump a tube of yeast into a beer at 12% already.

 

[cjgenever]

That's right. It would be best to make a starter on brew day to pitch at a lower abv, after fermentation character has been established by the primary yeast.

 

[trentm]

I thought about the 099. Never used White Labs yeast cause no store I've been to carries it (would have to order it online). Would it need a starter as if it was being used for primary fermentation? It'd seem kinda extreme to dump a tube of yeast into a beer at 12% already.

If you want to use liquid yeast for bottling, it would not require an entire tube. American craft breweries who re-yeast for bottling use around 100,000 cells per ml (~2 billion cells/5 gallon batch) and this would work out to about 2.5 ml of a White Labs yeast or 4 ml of Wyeast. For a beer this big you might consider doubling these volumes. The problem with liquid yeast is the questionability of the health of the yeast. In order to perform in a high alcohol environment it is very important that the yeast have healthy cell walls/membranes. Dry yeast have healthy cell walls/membranes and you can increase the health of liquid yeast by building a starter using a stir plate to supply constant O2. A starter without constant O2 does little to increase the health of the cell walls/membranes. Of course you already have too many cells in a commercial yeast pack so if you build a starter you will have even more. You could plan a brew day to coincide with your bottling or build a small starter with a portion of the yeast.

You might consider re-yeasting with your original US-05 yeast due to the known health of dry yeast. In this case you could rehydrate a pack of yeast and use 15 to 30 ml of the slurry.

*note: Unless otherwise noted, all yeast volumes above are for 5 gallon batches.

 

[cjgenever]

^^ agreed^^

I miss read the op's question. Not much yeast is needed. My concern is toxic shock going from storage to 12%

 

[mozart4898]

^^ agreed^^

I miss read the op's question. Not much yeast is needed. My concern is toxic shock going from storage to 12%

This is my concern too. I would use US-05 but I'm afraid that it'll be asking too much of it to add it to a beer at north of 12% and expect it to survive and carb it. Champagne yeast didn't do the job with my RIS last year so I doubt US-05 would succeed where champagne yeast failed.

I'm leaning a small starter of WLP099, maybe made from half a tube or so.

Only other possibility I've considered is kegging it and letting it carb, then bottling from that keg. Would prefer not to but it would be a guarantee of success.

 

[shtoive87]

I think using a krausening technique might be a good idea. Put the starter in the bottling bucket at high krausen with the sugar. The yeast are at their healthiest and working hardest at this stage.