In last week's post, you'll notice that I used Fast Pitch Starter Wort to grow a batch of actual Rochefort yeast from a bottle of Rochefort 10. That's the yeast we'll be using here.
The photo at the left is of my first round of starters for the yeast. I began with a 1 liter starter, then graduated to a one gallon starter to further grow the yeast.
If you don't have that or don't want to grow your own yeast, the original recipe recommended White Labs WLP530 Abbey Ale yeast. I'm sure that would do well with the recipe also.
10 pounds Belgian 2-row Pilsner (Weyermann)
2 pounds Caramunich I
1 pound Special B
4 ounces Carafa I malt
1 pound D-180 candi syrup
1.2 ounces of Styrian Goldings @ 5.4%AA
0.7 ounces of Hallertau Mittelfruh @ 4% AA
0.5 ounces of Hallertau Mittelfruh @ 4% AA
1/2 tsp. yeast nutrient
1/2 tsp. Irish Moss
1/4 of a Campden tablet
1 container of yeast grown from a Rochefort 10 bottle
Batch size: 5 gallons
Expected OG: 1.088 (20.95 Brix)
Actual OG: 1.093 (22.1 Brix) but 4.5 gallons of volume
Expected FG: 1.013 (4.83 Brix)
Color: 32.29 SRM
The actual Rochefort 10 beer reportedly has an original gravity of 1.097 or 22.9 Brix. It also reportedly has 27 IBUs, so this clone is likely to come out a little less bitter and at a lower alcohol content than the original.
Mash with 5.5 gallons
120 minutes at 154F
10 minute mash-out at 167F
Sparge with 2.25 gallons
I used The Grainfather for this recipe. Their mash calculation suggested 5.5 gallons of mash water for the recipe, which works out to 1.66 quarts per gallon. It also suggested 2.2 gallons of sparge water. While this figure seemed unusually high to me, I went with it.
I put 5.5 gallons of water in the kettle and added a quarter of a Campden tablet to remove chlorine and chloramine from the tap water. I let this work while The Grainfather heated the water to 154F. I came back an hour or two later, then stirred in all the grain and installed the perforated lid over the grain. I started the recirculation pump and left it.
At this point, I took some time to transfer a previous brew to a secondary fermenter, clean out that fermenter, assemble a new fermenter, etc. Then I even went out to dinner and came back. In the end, this mash ran for about 7 HOURS. I heated the sparge water and brought the wort to the mash out temperature of 167F. The grain was sparged using the heated water.
This yielded 6.5 gallons of wort at approximately 7 Brix. The Grainfather tends to boil off a little under a gallon in an hour, so I knew I was looking at a long boil to get the final volume I wanted.
The mash yielded a wort that was considerably higher in volume and lower in gravity than expected. BeerSmith suggested an 18.9 Brix pre-boil gravity, but I got more like a 7 Brix. I boiled the beer for about an hour before the first hops addition, to reduce the volume and increase the gravity.
60 minutes - Add 1.2 ounces of Styrian Goldings
20 minutes - Add 0.7 ounces of Hallertau Mittelfruh
15 minutes - Add Irish Moss, Yeast Nutrient, and D-180 syrup
7 minutes - Begin recirculating wort through the counter flow chiller to sterilize it
5 minutes - Add 0.5 ounces of Hallertau Mittelfruh
0 minutes - Turn off heat, remove hop spider, begin chilling and pumping to fermenter
My post-boil volume came out a little under 5 gallons, with a gravity of 22.1 Brix, which was a little higher than BeerSmith's suggested 21.1 - but the reduced volume probably accounts for that.
I oxygenated the wort for 120 seconds with a tank of pure oxygen and an oxygen stone. This, combined with the yeast nutrient would, I hoped, give the cultured Rochefort strain everything it needed to take off and begin fermenting. I have no way to be sure how many cells I have in the Rochefort culture, so no way to know if this is underpitched or overpitched. Since underpitching is common in Belgian monastery practice because it brings out the esters in the yeast, I'm not too concerned unless there are no signs of fermentation in the next three days.
After two weeks in the primary fermenter, I took a gravity reading of the beer with a hydrometer. I registered 1.030, which was higher than expected but it had not changed for a week. When I opened the fermenter, the yeast had completely flocculated to the bottom of the fermenter and the beer looked clear. After tasting the sample used with the hydrometer, I decided to forego secondary fermentation and just bottle it.
On April 9, I bottled the beer with 5 ounces of corn sugar and a packet of Lallemand CBC-1 cask and bottle conditioning yeast. Since I've had issues with some beers not seeming to carbonate as much as I'd like them to, I also dosed a few of the bottles with a Coopers Carbonation Drop to see how they turned out. All the bottles were placed inside closed containers in case they exploded.
April 3, 2016: After 2-3 days in the primary, I saw very little indication that the Rochefort yeast had awakened and started fermenting. The only vaguely similar yeast I had on hand at the time was a packet of dry Safale S-04 English Ale yeast, so I pitched that rather than leave the wort unfermented any longer. The next day the airlock showed signs of activity and there was a krausen on the beer. Today I did a gravity check and the reading had dropped from the initial 22.2 Brix to 13 Brix. This is with a refractometer, so the actual gravity is probably different.
April 9, 2016: The beer was bottled with CBC-1 and 5 ounces of corn sugar. On or about April 23, I'll chill and open the first bottle for carbonation and taste testing. The initial flat, warm samples from the fermenter did seem to resemble Trappistes Rochefort 10, though I'll want to do a side-by-side test in the future to confirm.
Taste Test and Post-Mortem
The color on mine is a touch darker than the real Trappistes Rochefort 10, which is slightly reddish. My clone inexplicably doesn't seem to get a head on it, while the real beer has a very thick tan head as you can see in the photograph at left. The head on the real beer stays there for quite a while. A bottle of mine, poured into a chilled glass, will generate an incredible amount of head like the original beer.
The aroma of my clone is perfect. To my nose, it smells exactly like Trappistes Rochefort 10.
The carbonation level on mine is much lower, except for the bottles with the extra carbonation drop. Those seem to have a nice effervescent level of carbonation. They still don't get a head on them like the real beer.
The flavor of the real beer, compared to my clone, has a bit more caramel flavor to it and has a bit more of a burn because it's quite a bit higher in alcohol content, but it's otherwise very close. To my taste buds, the bitterness level is pretty much identical as well. The lack of the caramel flavor and a nice head are pretty much all that I can complain about on this one.
The next time I brew the beer (and the fact that I know there will definitely be a next time, tells you something), here are the changes I plan to make:
- Replace some of the two-row pilsner malt with Caramel 40L to pick up the caramel and toffee flavors of the real beer.
- Avoid using Fermcap-S during the boil, in case that's the cause of my beer's lack of head.
- Add Carapils, Carafoam, and/or another grain with foam enhancing qualities in place of some of the 2-row, to see if that helps with head and retention.
I have to say that overall I am extremely happy with this beer. Friends who have tried it have used the words "outstanding" and "awesome" to describe it. Even if they didn't, I'm very happily drinking it myself - and that's the whole reason I got into home brewing. I wanted to make beers that I loved, whether anyone else liked them or not.