Way back in January I began an experiment to brew a porter fermented solely with Brettanomyces. This was a bit of a scary experiment as brett has a reputation for not playing nice with dark malts – the polyphenols in these malts can be converted by brett into other phenols – phenols which taste like burnt plastic, band-aids and dirt. In addition, brett tends to dry beers out, killing the balancing sweetness/mouthfeel that we look for when brewing with darker malts. If you read my original post you’ll see I did a number of things to reduce the risk of these issues – using dehusked dark malts, adding oats for mouthfeel, carefully controlling the sparge temperature, and so on.
Since posting about that brew a lot of my friends have been bugging me for a follow-up. But between travel, work and a couple nasty bugs, I’ve not been able to get around to a post – and to tell the truth, for most of the intervening time, I’ve not been able to taste or smell anything for most of that time anyways.
So how did it turn out? It is a good beer, but not exactly what I expected. . .then again, nothing about this beer after brew day was as expected….
Most people who have done all-brett ferments report that you need more yeast than with conventional ales, and that the ferment tends to be slow. Knowing that I did what others recommended – I aimed for a pitch-rate half way between an ale and a lager, I oxygenated well, and I tried to keep fermentation temperatures around 18C. I pitched the yeast in the evening, expecting that to be the first day in what was going to be a multi-week fermentation. So imagine my surprise the next morning (about 8 hours later) when I came down and the kraussen on the top of my 20L of beer took up nearly all of the remaining 20L of headspace in the brewing bucket! The next day the kraussen had fallen, and at the 48 hour mark the beer was within 2 points of completion, dropping to 1.014 from a starting gravity of 1.054. By the end of the week the gravity was down to the FG – 1.012 – but I went forward with the original fermentation schedule and kept the beer in the fermenter for 4 weeks before kegging and force-carbonating.
So, what does it taste like?
For a post that was supposed to be tasting notes, I’ve managed so far to not say anything about the beer itself. So without further ado. . .
Appearance: The ancestor of this beer was the very definition of a prototypical robust porter, so not too surprisingly it looks like a robust porter. The beer pours from the tap dark-brown in colour, but in the thicker container of the beer glass is midnight-black. Sadly, the head is minimal – I”m not sure what I screwed up, but even with the oatmeal in the recipe, the head is lacking.
Aroma: Roast notes dominate the aroma, but it is a “soft” note, and lacks the sharp edge I associate with conventional roast malts. No hop character is present in the nose, but there is a subtle hop yeast ester character.
Flavour: The big one – the taste – is not what I was expecting. The first thing I noticed was the strong brett character I was hoping for (and in some ways fearing) was not there – there is a subtle fuitiness with the expected orange/lime character described for this yeast, but had I not known it was brett, I would have assumed it was brewed with one of the fruitier English yeasts. The best news is that the medicinal/plastic phenols I was worried about are completely absent. But this came at a cost – the character of the dehusked blackprinz malt is not the same as that of the husked dark malts it replaced in the recipe. As dark as the beer is in appearance, in flavour it is more like a brown ale, perhaps pushing into brown porter country, but it is not the robust porter this recipe began as.
As soon as I began thinking of this beer as something other than a porter it became a much more interesting and enjoyable beer – appearance aside, this is similar to a classical English-style brown ale. Subtle roast malt character, fruity yeast esters, and a soft but balancing hop bitterness and flavour to fill things out. The other thing that is fun about this beer is how it changes as it warms; cold it is almost clean, but as it warms the esters come to the front and make themselves known.
The aftertaste of this beer is an interesting mix of roast flavours and sweet esters. The roast flavours fade faster, leaving a lingering sweetness that teases you until the next sip.
Mouthfeel: The mouthfeel of this beer is the only thing that is as expected – medium bodied, with a smooth creaminess imparted by the oats.
Overall: This is not the beer I was expecting to brew, but I am not disappointed. As a fan of the English styles I find the balance between the malt character, roast notes and yeast esters to be pleasing. The brett did impart a bit more ester character than would be normal, but it works well in this beer. This recipe needs some work, but rather than being a tosser, its just in need of some tweaking.
What would I do different?
While this made a good beer, I am disappointed at the relatively mild brett and roast character imparted by the yeast. I was hoping the fruity notes would come out more, giving a beer with up-front chocolate roast notes (from the malt) and fruit notes (from the brett). While the fruit notes are there, they are not exceptional and could be mistaken as nothing more than a fruit English yeast. There is a simple solution here – pitch less yeast and let the beer ferment a few degrees warmer. And now that I have a few more brett strains – including some that have flavour profiles that may work better with dark malts (cherries from wyeasts B. lambicus, as well as B. trois and B. claussenii), I can perhaps find a yeast with a more appropriate flavour profile.
I was presently surprised that I didn’t develop some of the phenol characters I was worried about, but this did come at the cost of making a pitch-black beer that tastes like a brown. To achieve a stronger roast character, in the future I would consider using a dehusked:husked dark malt ratio closer to 1:1, instead of the 3:1 used in this recipe. Alternatively, I could double the blackprinz (relative to the amount of chocolate malt that would normally take its place), although I’m uncertain of the flavour profile that would create.