Beer math is hard.
Having recently ballsed up on a number of mathematical fronts when brewing [Bad Habit](#14 Bad Habit), my first attempt at a beer with a substantial amount of non-malt fermentables, I was determined to redeem myself with Busy B, a braggot-cum-honey tripel.
Things started promisingly enough. The brewday was at worst uneventful, although my OG was a few points short of the planned-for 1.056, hitting 1.053 instead. I think tacking on an extra 5 minutes of boiling time is going to become a standard part of my regimen – another samaxim. Mashing at the low end at about 65 C, I had a vigorous fermentation going within 36 hours and hit 1.012 after 5 days for an initial ABV of about 5.4% and attenuation of about 77%.
My plan was then to add the requisite 1117g of honey. Due to planning a mead which didn't get made, I happened to have 3lb (1362g) of inoffensive Waitrose clover honey on hand. Opinion seems to be split on whether it's necessary to pasteurise honey before adding it to fermenting beer. Being somewhat inebriated when the time came, I opted not to. From a sanitation standpoint, it seems not to have been a terrible decision, because the krausen had reached nearly 5 inches in height by the following morning and the yeast certainly seemed happy enough. Since there was no activity in the airlock, I have to assume nearly all the honey was fermented in the space of about 9 hours overnight. That's probably enough yeast to orchestrate a hostile takeover of Tate & Lyle's.
I spent a while stirring in the honey so that I could get an accurate hydrometer reading, so I was bemused to find that it only reached 1.020, and can only guess that most of it sank to the bottom (I can't imagine that this would have put it out of the reach of the ravenous yeasties, so the only loser in this story is my hydrometer).
How much did the honey actually contribute to the fermentability of the wort? I previously calculated the gravity points the honey would contribute based on its fermentability vis-à-vis that of barley, but I eventually got around to do it a bit more scientifically, by calculating the original gravity of the Waitrose clover honey I used. I dissolved 100g of honey in 500ml of water, and got a hydrometer reading of 1.055. By the power of mathematics (and Greyskull), 1362g in 17.5 L gives about 21 gravity points:
(1362/17500) / (100/500) / * 55 ≈ 21.4
So, 53 + 21 gravity points gives a total OG of 1.074. This is 6 points short of the planned for 1.080. Three of those 6 are down to an underefficient grain mash (or slightly diluted wort – which amounts to the same thing), so the other three must be down to underestimating the gravity of the honey. I think where I went wrong was in assuming that since 95% of the sugars contributed by honey are fermentable, that this also means that 95% of its mass is sugar. I'm still puzzling this one out, but as my final gravity was 1.010 (giving a very dry overall attenuation of 86.5%), and I just about nailed the ABV at 8.4%, I'm not overly concerned.
I tried yet another method of bottling this time. Stirring the sugar syrup into the FV on Bad Habit led to disastrously inconsistent carbonation (much like my experience stirring in the honey – I think there's a lesson there), so this time I decided to use a bottling bucket. Rather than siphoning the beer, I connected the hose to the tap of the FV and let it run through. No splashing, no starting and stopping, no wondering whether the siphon is far enough into the bucket, or too far and sucking up all the sediment. If the bottles carbonate evenly, this might be The Way.
I ended up with over 16 L in bottles, which was more than anticipated – yet another indication that the wort was too diluted – so I will be starting to sample Busy B after about a month in the bottle for the sake of science. No doubt the Western World will be waiting on the edge of its collective seat for the next few weeks.