Monday, December 27, 2010

Christmas Eve and Boxing Day brew day: Gust Front Leipzig-style Wheat

I'm a bad scientist.

In a controlled experiment, you want to keep everything constant except for your independent variable. This past weekend we brewed our Leipzig-style wheat (a.k.a. Leipziger Gose) for the second time, and I intended to do everything the same way I did our last Gose except for one variable: how we kept the wort heated during the inoculation phase. In reality, due to a combination of oversight, laziness and unexpected error, a few things are different the second time around. Nonetheless, I hope to end up with five gallons of delicious Gose a month from now.

If you want a full rundown of what Leipziger Gose is and how I brew it, I recommend you revisit this post. But if you're into the whole brevity thing, here's the process in a nutshell: you mash and sparge, pitch lactobacillus (which sours the beer), let it sit for roughly two days, and then bring the beer to a boil and finish it like a normal beer (add hops, cool, pitch). The trick is keeping the beer warm for the lacto; bacteria likes a warm environment, and it seems that both the temperature and length of inoculation contribute to the level of sourness.

The last time I brewed the Gose I simply cooled to 110°F, wrapped the carboy in a bunch of blankets, and hoped that it didn't lose too much heat (I ended up a little over 90°F by the end of the two days). My last Gose had a definite sour kick, but it still wasn't as sour as our favorite Gose. I recently bought some new toys (as discussed in my last post) and now I'm hoping to dial in these variables so I can consistently produce a desired level of sourness.

So how did things go? Well, on my first brew day (Christmas Eve) things started out just fine. I mashed in at 152°F and added 1/4 tsp. of acid blend. I got off to a late start and needed to be done in time to head off to Christmas Eve candlelight service so I skipped the decoction I employed the last time I brewed the Gose--that would be unintended variable #1--though I did use a mashout. After 40 minutes I went to sparge and--ugh--my manifold came undone AGAIN. I've fixed the problem on my large mash tun but it's still an issue on my small mash tun (I think I just need a stainless steel tube to run between my interior hose and my exterior outflow hose). Anyway, I couldn't get the damn thing to connect so I had to bust out my large mash tun which, for a 5-gallon batch of relatively low-gravity beer, is a bit too big. As such, when I sparged, I ended up with a somewhat turbid wort due to the shallow grain bed. So that was unintended variable #2.

I boiled for 15 minutes and miraculously managed to cool down to 110°F with my plate chiller (that was more difficult than you'd think because I had to constantly adjust the flow rate to get the temperature right and my ThruMometer obviously doesn't go up to 110°F). My gravity at the time was 1040. I also collected an extra 1/2 gallon for my yeast starter. I was now ready to pitch my lacto starter.

This brings me to unintended variable #3. The last time I made my lacto starter, I would occasionally dip it on a hot water bath to keep it over 90°F. This time around I discovered that my crock pot, set to "warm," kept it at a consistent 105°F. Also, last time I made my lacto starter, I only made 500mL; this time I made 1000mL. And to top it all off, I can't find my pH meter so I don't know what the actual pH of my starter was (though I have a sample in the fridge so I can find out when my new meter that I just ordered arrives). So I pitched a bigger--and likely more acidic--lacto starter this time around.

Once I pitched the lacto, I immersed the carboy in a hot water bath in a cooler as pictured to the right. I had an aquarium heater in there that would make sure the bath temperature never dropped below 90°F, and I covered the whole thing with a couple blankets. I also used a bucket heater two to three times a day to bring the temperature back up to 110°F, so most of the time the actual temperature of the wort was somewhere between 95°F and 105°F.

After roughly 45 hours, I took the carboy out of the hot water bath and siphoned the wort back into our brew kettle. I can't remember if this happened the last time, but this time around I found a white film on top of the carboy (as you can see below). I also noticed that there was a sickly sweet and vegetal smell, sort of like cream of tomato soup, which I distinctly remember from the last time I brewed so that didn't worry me. Since I had done a 15-minute boil on the first day I finished off with a 75-minute boil to make sure to drive off any DMS (which I believe is the source of the vegetal smell). I also found a little scum floating on top of the beer when the boil started (not sure if it was the film from the bacteria or protein due to the thin grain bed) so I skimmed that off.

I added hops at 60 minutes, Irish moss at 15 minutes and the freshly-ground coriander (1/2 oz.) and sea salt (5 g.) at 2 minutes. I chilled to 65°F and found the gravity to be 1047 (my target exactly). I oxygenated and pitched a 1/2 gallon starter of WLP320 yeast that should bring my original gravity down to 1046. This morning when I woke up the beer was fermenting away.

I kept samples of the lacto starter, the pre-boil wort and the post-boil, chilled wort, so hopefully I'll get pH readings of each of those so I have a better idea of how this beer compares to the last. All I can tell you for now is that I tried the post-boil sample and if my memory serves me correctly it had a distinct tartness I didn't pick up from the last Gose pre-fermentation. Will this indeed be more sour? I suppose I'll know in a couple weeks!


Blogger Señor Brew™ said...

I was just reading your keg inventory--too many empty kegs! I have the opposite problem, I don't have as many freeloaders, I mean friends, in CA as I did in Chicago. All my kegs are full--come visit and drink my homebrew!

6:08 PM, December 28, 2010  
Anonymous Brian said...

I will be curious how this turns out. I have had a gose on my brew list since last summer when I tried Kevins at GB.

I am thinking of brewing one of these for early March consumption, what is the kettle to glass time in your opinion? How long to peak?


12:15 PM, January 05, 2011  

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