So I’ve finally joined the 21st century. After 15 years of brewing with a cool box mash tun, I’ve taken the plunge and bought a grain pipe system. I went the whole hog and bought a Grainfather G70 V2. The ‘V2’ refers to a redesign just introduced in the last few months. The big difference is that the overflow pipe has been removed. That was particularly attractive to me, as I am usually making German beers, and more often than not pulling decoctions, so not having to negotiate the pipe while doing so seemed like a real bonus.
The first step: a little R&D
My plan was to brew the most complicated and disaster-prone beer I could think of. If I can do that, I reasoned, I can do anything. Dunkel Weizenbock fits the bill nicely, a big beer, usually over 7%, with a large proportion of (undermodified!) wheat in the grist. My model was Aventinus from Schnieder in Munich. That one comes in at 8.4%, but is beautifully balanced: alcohol warmth, dark malt flavours and the banana phenols in elegant interplay.
My recipe is taken from the excellent Brewing with Wheat by Stan Hieronymus. He says that Aventinus is made with 60% wheat malt and 1% chocolate for colour. I have heard elsewhere that Schnider actually use roasted barley for the colour, to avoid roasty flavours. Hieronymus also says that wheat crystal malt will do the job nicely, but I opted for wheat chocolate, something that probably didn’t exist when Schnieder first formulated their recipe in the early 20th century. Here is a run down of my malt bill, for a 50L brew:
10kg wheat (Weyermann)
4.5kg Maris Otter (British, obviously)
2.5kg Munich II
250g wheat chocolate
The mash schedule was exactly as Hieronymus advises:
Mash in 35°
Acid rest 45°, 10 minutes
Raise to 64°, pull decoction
Return to mash and raise to 71, 20 minutes
77° for mash out
Mash problems - where to start? Actually it all went quite smoothly. Getting the liquor to recirculate though the grain bed proved tricky especially at the start, but I choked off the pump with the upper tap and soon found the right balance.
The decoction was very thick, but I’ve found that so long as you stand over it and stir regularly, there is little risk of burning.
And so to the sparge. I read in one Weizenbock recipe that if the sparge lasts more than three hours, you should reheat the sparge water. An ominous sign. In the event, the sparge was slow, but not that slow, perhaps 40 minutes. One advantage of the Grainfather is that most of the water is in the mash, so the amount of sparging required is significantly less. Just as well for this beer.
A 90-minute boil: this is a malt-forward beer, so there is no point in rushing this. Hops: 73g of Hallertauer at 80 mins; 27g at 15 minutes.
One final problem, when I pumped the wort through the counterflow chiller (which works brilliantly, by the way, much faster than my previous immersion chiller, and far less water used) a thick sediment of cold break accumulated on the hop filter. I had to scrape this off as I went along with the mash paddle, but when I came to clean the machine afterwards, there was a similar thick residue beneath. Clearly, this machine isn’t designed for such a viscous, protein-heavy beer, but then, what is?
Fermentation at 17°. About a day after pitching the yeast (Wyeast Weihenstephan) I removed the lids from the fermenters for open fermentation. Those went back on after about a week, at which point I raised the temperature to 23° for diacetyl rest and full fermentation.
I still only managed a final gravity of 1020, where Schnieder apparently finish at 1012 (how do they do that?). Still, the extra body is quite welcome, and doesn’t noticeably detract. Original gravity was 1076 (exactly the same as Aventinus) and so the ABV came in at 7.4%.
That’s plenty, of course, and I’m very pleased with the results. The banana is present without venturing into bubblegum territory. The malt profile is gorgeous, rich but not too roasty. And the alcohol does exactly what it should, it warms without overpowering. In fact, the alcohol is in the background with this beer, a surprise given its sheer quantity.
What would I change next time? Not much. I might drop the bittering hops by about 10g for better balance. I am also considering a second decoction, to increase the malt profile even further. That’s not necessary, of course, and this recipe would probably work without any decoctions at all (though the sparge could get tricky). But the Grainfather G70 V2 is so accommodating for pulling decoctions, it seems a shame not to. Plus, it’s fun! Real hands-on brewing, even on my new, semi-automated system.
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