Brew day: Cloud-to-Ground Weizenbock and Thunder Snow Weihnachtsgose

Gather around, my son, and I shall tell you a tale...

Okay, so it's not THAT much of a tale, but it's certainly a bit of a deviation from my usual German-style brewing which, despite long brew days with step mashes and decoctions, is fairly routine (this time there's a reason I waited over three weeks to blog about a brew day that actually took place on Oct. 13th). Our Novemberfest party is coming up in a couple weeks, and in addition to our Pilsener and Novemberfest Bock (more on that in my next blog post), I decided to go with a Weizenbock for our third offering.

Meanwhile, a few weeks ago I came across this article in Imbibe Magazine about Leipziger Gose (a style I brew and blog about regularly, if you're new to these parts). The article mentions that Cascade Brewing in Portland actually brews seasonal Goses. Now the last time I brewed a Gose I did a split-batch where I made five gallons of Gose and five gallons of Hefeweizen from the same runnings, so it suddenly occurred to me: I could do a split-batch with my Weizenbock grain bill and make five gallons of strong, dark Gose that I could spice with Christmas spices to make a Christmas beer! (And for the record, dark Gose is not without precedent... The only Gose brewer still producing Gose in its hometown of Goslar makes a dark Gose which I blogged about here).

So, I had everything all planned out. The only trick was that, when I make my Gose, I inoculate it with wort with lactobacillus for a period of time before boiling, adding the hops and pitching. I've found between three and four days to be the sweet spot for getting the sourness I prefer out of a Gose (you want a sharp tang that is cut by the mineral quality of the salt addition, but you don't want it so sour that it's not drinkable). However, I've always brewed by Gose at around 1050. Would it sour at the same rate if it were at 1080 instead of 1050? Would it take longer in the same way that it takes yeast longer to ferment a stronger beer? And would the added gravity mean that I would need more acidity to get the same perceived sourness, in the same way that a higher-gravity beer needs more IBU's to have the same perceived bitterness?

Well, I was going to be mashing on Sunday, and Wednesday was the only day where I could come straight from work and do the boil, so it was going to inoculate for three days. If it wasn't sour enough, then so be it.

For the brew day I decided on a single decoction similar to what I used for our Step Leader Hefeweizen.  I mashed in at 122°F and pulled an 18-qt. decoction which rested for 15 minutes at 160°F before boiling for a half hour. I returned it to the mash to raise it to 152°F.  After a fifteen minute rest, I raised the mash using direct heat up to 159°F for another fifteen-minute rest. I then raised it up to 170°F for the mash-out. After a sparge of roughly an hour and a half I collected 11.5 gallons at 1065. Due to the size of my mash tun, I was planning on adding 5 lbs. of wheat malt extract to the boil, and 1065 was a bit over my pre-boil gravity estimate but under the amount of volume I wanted to collect, so I added a gallon of water to the boil.

I added five pounds of wheat malt and brought the wort to a fifteen-minute boil, I collected roughly six gallons, chilling to around 100°F with my plate chiller. The remaining six or so gallons were boiled for another hour with a single hop addition at 60 minutes. I added Irish moss around 15 minutes and chilled to around 72°F. I collected a half gallon in a growler into which I pitched an Activator pack of Wyeast Weihenstephaner Weizen yeast. The rest I chilled overnight in my chest freezer to drop to around 60°F. To my surprise, I came ten gravity points above my target, hitting 1090. Yeah, that's a BIG Weizenbock. I added the active starter the next morning.

Into the other six-plus gallons I pitched a lactobacillus culture and I kept the carboy immersed in a hot water bath at between 100 and 115°F for three days. Wednesday evening I returned the wort to the brew kettle and this is where things got interesting... I took a sample to measure the acidity and my pH meter read 2.5! Now I must confess that my pH meter is rather cheap and, while I calibrated it, it's probably been six months since I've used it so the probe may be bad. However, I took pH readings of a lager I have on tap, tap water, and some fresh cider, and each reading was consistent with the range predicted by various online sources. And when I tasted it, it really seemed about as tart as lemonade.

Anyway, I added hops and 10g of various salts (grey sea salt, pink sea salt and kosher salt) and boiled for sixty minutes. After the boil, I chilled to around 72°F and ended up with about 4.5 gallons of wort at 1084. It also still had an acidity of 2.5. Concerned that yeast wouldn't actually ferment at that high of an acidity, and having a crazy high gravity, I figured I could dilute with water and Kräusen (i.e. the actively-fermenting Weizenbock), but an online calculator indicated that would only get me to 2.6 (damn logarithmic scale!). But I decided to add roughly 3/4 gallons of water and 3/4 gallons of Kräusen anyway just to give the yeast a bit of a head start. And sure enough, it was going 24 hours later.

So what's the situation now? Well, I kegged both beers this past Sunday. I took a gravity reading of each and found the Weizenbock was still around 1030 and the the Gose was closer to 1050. As such, when I kegged I left the release valves open. Sure enough, the next day Kräusen was spewing out of the release valve of the Gose keg. The Gose was also interesting because it had a strong peach-like flavor; gonna be curious to see if the acidity leads to odd flavors from the over-strained yeast. I'll check the gravity of each again in a couple days.

I guess the moral of the story for now is that yeast is pretty damn resilient. How will the Gose turn out? Not sure, but worst case scenario, if it's too sweet for my taste I'll just brew up a batch of Dunkelweizen (or possible an amber wheat with a neutral yeast strain) and blend. Either way, it should be a Christmas beer to remember.

EDIT (11/4/12): Checked the gravity of each beer last night... The Weizenbock was down to around 1028 and the Gose around 1042. I diluted the Weizenbock with a half-gallon of bottled water to drop the OG to 1080 and the FG to 1024.