So I was tinkering around with brewing Jamil's Orval clone using extract. Considering that a dry finish is the hallmark of this beer, I did the math on how much extract to replace with sugar to achieve the FG listed in the book of 1.011, and got some surprising results. Follow my logic and tell me if I'm wrong.

Jamils recipe is as follows:

OG 1.057
FG 1.011
ADF:79%

% Amount Name Origin Extract SRM
-----------------------------------------------------------------------------
74.7 7.40 lbs. Generic LME - Light Generic 1.043 7
10.1 1.00 lbs. Cane Sugar Generic 1.008 0
15.2 1.50 lbs. CaraMunich 60 France 1.006 60



The cane sugar will ferment to 0. The Caramunich will not ferment at all, and contribute all of it's 1.006 extract to the final gravity. Therefore, if I'm shooting for a final gravity of 1.011 I need the LME to ferment down to 1.005.

Assuming an approximate 80% fermentability for the extract (which was my observation from my extract days) the extract in the recipe will ferment down to 1.009, putting the final gravity of this recipe at 1.015. Here's where I run into trouble. I need to replace enough of the extract with sugar to bring the gravity down 4 points. Assuming 80% fermentability of extract, that's 19 gravity points of extract that I need to replace with sugar, which works out to 2.5 lbs of sugar.. So, after making my substitution, here's the malt bill:



% Amount Name Origin Extract SRM
-----------------------------------------------------------------------------
45.4 4.15 lbs. Generic LME - Light Generic 1.024 7
38.3 3.50 lbs. Cane Sugar Generic 1.027 0
16.4 1.50 lbs. CaraMunich 60 France 1.006 60



2.5 lbs of substituted sugar, plus the pound in the initial recipe makes for 3.5 lbs of sugar! Almost 40% of fermentables. As an aside, all of these numbers are specified as prior to the brett addition in this beer: "attenuation will increase past this with the addition of Brettanomyces," so we can't attribute any unexpected attenuation to brett.

All of the calcuations seems sound, and I'm comfortable using that 80% approximation. The breiss website actually lists the fermentability of their pilsen extract at 76%, but a less fermentable wort would require the substitution of even more sugar, and wouldn't change the calcuations much. Am I missing something? Help me find the hole...in my logic.

My suggestion would be to review the section on Orval in Brew Like a Monk to find out what they are doing. I don't recall off the top of my head, although they do use quite a bit of sugar, I don't think it was that much.

Alan

I wouldn't worry too much about replacing the malt with sugar. The brett is going to dry it out no matter what, right to where the brett wants to dry it out to, which will probably be 1.007 or lower, if you give it time. It will eat right through detxrins. So the only tricky part is not giving it way too much food, or it might be too overwhelmingly bretty.

My suggestion would be either to brew it as is and replace the grain with extract, or bump the sugar up by a half pound and the malt down proportionately. Don't worry, if you use brett the beer will not be too dry! Not as long as you age it long enough. And you want to keep it fairly cool (mid 60's if possible) for the secondary or again, the brett flavor can get way too funky.

+1

The Brett makes the beer seem dryer when the FG is relatively high. I've got a 1.064 beer that I mashed at 156° that fermented to 1.018 with lager yeast. I added the Brett at kegging and let the Brett carbonate the beer in the keg as a secondary fermentation. The Brett only brought it down to 1.014 but it seems really dry.

I think the Brett needs more oxygen to get it really drier (barrel fermentation or carboy with wooden dowel, etc.).

Has anyone ever taken a final gravity on Orval?