So, another of my early beers, my Munich Dunkel, did not come out perfectly. I did several things new to this one that I haven’t done previously. This was my first formal lager (I’d only ever used California lager yeast previously) and I had a couple of issues with that, mostly because of a death in the family. This was also the first time that I’ve done multiple decoctions on a beer. For this beer, I did a double decoction. I have explained the process previously in my Duesseldorf Altbier post, so I won’t get into that here. The beer turned out okay, but it hasn’t performed as well as I’d like in competition but I think I know what I can do to fix it in the future. At any rate, here we go.
So, for this, I had the intention to use 100% Munich malt, though I did use a small cap of Carafa Special III, which is the darkest of the german dehusked coloring malts. I also only did a bittering charge of Hallertauer hops in this as well. Colorwise, this came out a touch on the lighter side, even with the color adjustment, but it’s not that huge of an issue. As I stated, I utilized a double decoction and I mashed in around 143F for a Beta-Amylase rest, which aids in breaking down the longer chain sugars into easily fermentable shorter chains such as maltose and glucose. I then pulled the decoction after ~10 minutes and raised to boiling. I generally don’t hold the temperature for long (if at all) in my decoctions because, as the temperature raises, it progresses through the saccharification temperatures and continues until the enzymes are denatured. Aside from this fact, the decoction is very thick and inefficient for conversion anyway and the mash liquor is fairly rich with enzymes for conversion once the decocted portion is returned to the mash. I boiled for 15min then returned to the mash, bringing the temperature up to the Alpha-Amylase rest temperature, around 158F. The purpose of the Alpha-Amylase rest is to continue to break down the long chain sugars at random intervals, yielding maltotriose, maltose & glucose. The former is a tri-saccharide and difficult for yeast to digest and contributes to mouthfeel, as do the limit dextrins that are produced in the conversion process. After an additional 30 minute rest, an additional decoction is pulled in order to contribute additional color and complexity and to raise the temperature to mash out temp.
One mashing is complete, and the slow runoff, the boil and chilling take place. For this beer, I made a gallon starter of yeast to ensure I had sufficient healthy yeast to ferment this beer. It’s not a large beer, but at the lower temperatures of lager fermentation, it is needed as the growth phase is slowed. By pitching a large count of healthy yeast, you ensure a healthy start to fermentation. I decanted the starter beer from the top of the slurry and pitched directly into the wort at ~50F. I maintained this temperature utilizing a swamp cooler technique involving a tub of water, a t-shirt to wick the water up the sides of the carboy and several ice packs to hold the water at the primary fermentation temp of 50F. The problem arose when I learned that my grandmother had passed and I had to make a decision. It was bitterly cold outside, so I opted to open the window in my brewing room and closed the door. Upon returning 5 days later, I found the swamp cooler system completely frozen, along with parts of the beer. Rather than throw it away, I let it thaw back down and see if the yeast was still active as the cake hadn’t frozen. As it turns out, it was still working (albeit slowly) and it finished out the beer. The main issue initially was that it was a bit diacetyl laden, which subsided after a diacetyl rest at ~66F and a long lagering period. It has steadily improved, but is far from the beer I had envisioned. I think next time I’ll better monitor the fermentation temps to ensure full yeast health and I may also change the yeast as well. I utilized the Munich Lager yeast for this, but there is something that I don’t particularly care for too much in this one. At any rate, I think the mash process was successful at least!
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