I finally got around to brewing this, eight months after the successful re-brew aired. It definitely makes for a long brew day!
To start off, I created a recipe in beersmith that would produce enough wort for a double-size batch at an OG of 1054 (figuring that's what I'd get if I blended equal amounts of the 1060 ESB and the 1048 London Pride). I adjusted the original grain bill for my own batch size, efficiency, and boiloff rate. Usually I want about 6.75 gallons into my boil, and I end up with about 5.5 gallons or a little less in the carboy after evaporation and trub left in the kettle. My malt bill was 20 pounds of Maris Otter and 1 pound, 1 ounce of the British crystal 80.
I doubt if it matters much, but I noticed on listening again that Fuller's targets an evaporation rate of 7-8%, while mine is usually somewhere around 12%.
Then I created two other recipes in beersmith, with proportionate amounts of the Maris Otter and crystal malt relative to the first recipe, one to give me the 1060 of the ESB and one for the 1048 of the London Pride. Those two recipes gave me the pre-boil gravities I should target. Based on the podcasts and the reading I've done on partigyles (Randy Mosher has an article on the net about them, and there's also Tom's Partigyle Cipherin' sheet), I knew I was going to have to do some blending to get my pre-boil gravities.
The only real problem I encountered was at mash-in. Both beersmith and the calculator at rackers.org told me I would have about half a gallon of space left in my 10G mash tun with a thickness of 1.5 quarts/pound, but I wound up not quite being able to fit all eight gallons or so of strike water in the tun. (Fortunately I do things backwards from most people and add grain first, then stir in water). I figure I got about seven gallons in, or maybe a bit more. Regardless, I still hit my mash temp of 149. The only downside was that I needed to sparge a bit more than I had planned.
The water in the recipe is described as 'Burtonized', which is nice and vague. John Palmer's spreadsheet suggested that about a gram or so of gypsum would be appropriate for my water, so in it went. In the interview, the Fuller's person said they treat their water in varying ways until they get the profile they want, but didn't give any specifics. My mash pH was 5.3 all the way through the first half of the runnings, and wound up at about 5.8 when I got to the end.
My hope was to get almost all of the ESB runnings before sparging. Even if I had gotten that last gallon into the tun, I would have had to sparge, because the grains absorbed more water than expected.
I did have a bit of an equipment snag - the only vessels I have capable of holding 6.75 gallons are my kettle and mash tun. I had to run the later runnings off into a bucket and a smaller pot to hold all the liquid I needed.
After the initial run-off of 6.75 gallons, I had a 1068 wort, so I blended with the later runnings until I got down to my pre-boil gravity. I boiled the ESB wort and hopped as the recipe indicated. I was a little concerned about hopping, because beersmith indicated that the IBUs were a little low. However, the interview with the guy from Fuller's didn't actually give IBUs, and if I switched my options from Tinseth to Rager they looked a lot better. I wound up just adjusting quantities for the alphas in the hops I had bought online and not worrying about IBUs at all.
OG out of the kettle for the ESB was 1061. I chilled as far as is easy in St. Louis in July and put the carboy in the fermentation fridge to come down the rest of the way to the 64F pitching temp.
When I combined the later runnings from my multiple small vessels in the brew kettle, my pre-boil gravity was about six points low. I'd also managed to run off more than my ideal 6.75 gallons. I'd talked about partigyles with someone from the LHBS recently, and he said it would be good to be prepared to be low on the second beer. I made up the difference with DME, boiled, and hopped as indicated, except I added a couple more grams of bittering hops, since I had a slightly larger amount of wort than normal.
OG out of the kettle for the London Pride was 1047. Once again, I chilled as far as easy and let the fridge make up the difference.
When both worts hit 64F, I pitched a one-liter starter of 1968 harvested on Monday from a brown ale into each. I plan on following the unusual fermentation schedule as described on the show.
One concern I'd had before today was color. I didn't get a good sense from the pictures Beersmith generated that the SRM from either beer was going to be right. However, the colors of each wort match my recollection of the real thing perfectly, as the first runnings are substantially darker than the later runnings used for the London Pride.
If I were to do this again, I'd want to be able to do two boils at once. There's a long time spent running off wort and blending before the ESB gets to the burner, and the London Pride sat even longer. Both had an opportunity to cool quite a bit compared to a non-partigyle wort, so they took longer to come to a boil. Overall, it was about a ten-hour brew day.
There's a pub not far from me that serves both ESB and London Pride on cask. I am looking forward to going there and having a pint of each, and then comparing against mine when I get home - I doubt they're liberal enough to let me bring mine in for a triangle test.
