Gravity WAAAAY off for Russian Imperial Stout

[Baldhead Brewer]

I just brewed an Russian Imperial Stout that I had converted to partial mash from an all grain recipe using Beersmith2. The style is kinda big, and I kept tweaking it until Beersmith estimated my OG to be 1.087. I was very surprised after I had bottled it up and topped off the water, to get an OG of 1.109! And indeed, the wort was syrupy in consistency. Why was Beersmith so off on this one? I'm not really sure my yeast can keep going on a beer this big. I am considering splitting it into two carboys and adding more water, but I don't want to mess with it after fermentation has started.

If anyone wants to check the recipe and tell me what I did wrong, I shared it here: http://beersmithrecipes.com/viewrecipe/259003/imperial-stout-partial-mash-alt

[Baldhead Brewer]

Sorry let me amend that: my OG was 1.119, not 1.109. It was freaking thick!

[Oginme]

I downloaded your recipe and the first thing that pops up is that you still have the recipe type set as an extract.  When I switched it to a partial mash, the OG jumped up to 1.114.  The program treats specialty grains in an extract recipe as being steeped only, so you do not get the full value of the base malt you have in the recipe.

[Baldhead Brewer]

Uuugggh of course, I do t know how I missed that. I must be tired. Yup, that's the error. Ok thanks.

[MaltLicker]

I've read that for really big OG's, it's OK to add more oxygen in the first 12-18 hours to keep the growth phase going. 

You could also pitch more re-hydrated yeast to boost the cell count. 

Beer yeast can handle 1.114, if enough of them are pitched or grown at the outset. 

[Scott Ickes]

I've read that for really big OG's, it's OK to add more oxygen in the first 12-18 hours to keep the growth phase going. 

You could also pitch more re-hydrated yeast to boost the cell count. 

Beer yeast can handle 1.114, if enough of them are pitched or grown at the outset.

MaltLicker knows of what he speaks!

I harvested and rinsed from a previous batch a half gallon of London Ale Yeast.  I then made a gallon and a half starter with it three days before pitching it into a 1.142 Tootsie Roll RIS.  Of course I oxygenated the wort really well before pitching.  I then hit it with oxygen again at 4, 8 and 12 hours.  Within four days it was at 16% alcohol.  I think that yeast is advertised as only alcohol tolerant to about 11.5%.  I did have to fight to keep the fermentation temperature down though.  It was a roiling, bubbling, conflagration of a ferment.  I had the fermenter in my utility sink with about 4 inches of cold water in it and a damp towel wrapped around it with a fan blowing on it on high.  I used an 8 gallon plastic bucket fermenter for the primary, so I never had to use a blow off tube.

I pitched a starter of champagne yeast into it with my bottling sugar.  It may take 2-4 months to carbonate, but it actually tasted good flat.

If you make your yeast happy, they can do wonderful things.