I'm glad to share the details.
I did do a second version of this beer a couple months later, with some minor recipe tweaks:
Recipe: Roasted Chestnut Porter v1.1
Style: Brown Porter
Type: All Grain
Recipe Specifications
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Boil Size: 4.50 gal
Post Boil Volume: 3.90 gal
Batch Size (fermenter): 3.50 gal
Bottling Volume: 3.28 gal
Estimated OG: 1.051 SG
Estimated Color: 25.3 SRM
Estimated IBU: 29.2 IBUs
Brewhouse Efficiency: 75.00 %
Est Mash Efficiency: 80.4 %
Boil Time: 60 Minutes
Measured OG: 1.053 SG
Measured FG: 1.008 SG
Measured ABV: 5.9 %
Ingredients:
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Amt Name Type # %/IBU
2 lbs 8.0 oz Chestnuts (20.0 SRM) Adjunct 1 31.7 %
4 lbs Pale Malt, Maris Otter (Thomas Fawcett) Grain 2 50.8 %
8.0 oz Carabrown (55.0 SRM) Grain 3 6.3 %
6.0 oz Caramel Munich 60L (Briess) (60.0 SRM) Grain 4 4.8 %
4.0 oz Brown Malt (65.0 SRM) Grain 5 3.2 %
4.0 oz Carafa II (Weyermann) (415.0 SRM) Grain 6 3.2 %
0.75 oz Challenger [7.60 %] - Boil 50.0 min Hop 7 29.2 IBUs
0.25 oz Challenger [7.60 %] - Boil 0.0 min Hop 8 0.0 IBUs
1.0 pkg London ESB Ale (Wyeast Labs #1968) [124. Yeast 9 -
Mash Schedule: BIAB, Medium Body, Dunk Sparge
Total Grain Weight: 7 lbs 14.0 oz
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Name Description Step Temperat Step Time
Mash In Add 8.51 qt of water at 170.9 F 152.0 F 60 min
Mash Out and Sparge Add 11.80 qt of water at 181.5 F 168.0 F 15 min
The second batch turned out even tastier than the first; I used the same basic procedure with the chestnuts as I did on the first. I have a few bottles of this left and I'm still milking it
I also did a test using 50:50 chestnuts to pale malt. Basically, I was trying to measure the actual extraction from the chestnuts, since I knew (roughly) what the pale malt would give up, and everything beyond that had to be the chestnuts. This was all a precursor to brewing this semi-commercially.
Last April, I did a one barrel batch of the above recipe (or very similar to it; only had Briess malts to choose from) at a small local brewery. The beer turned out great and was pretty popular--it sold out in no time. I'm now an assistant brewer there and will eventually be the pub brewer, as we're expanding to add a bigger production facility. I don't know that we'll ever step up to a 15-barrel batch of it, but I intend to do it again at the pub
Let me know if you need any other information--thanks again for asking!