February 20, 2010 - Munich Dunkel

On February 20th I brewed a Munich Dunkel using a decoction mash and 100% Munich Malt. This is the first decoction mash I've done since diving into the BJCP study cycle that has caused me to delve much deeper into brewing books.

This recipe consisted of 23lbs of grain, 78% Munich 10l and 22% Munich 25l. I dove into a decoction mash hoping to both maximize the extract from munich malt and get the 'beguiling maltiness" described in Greg Noonan's "New Brewing Lager Beer".

My goal was a double decoction mash with an initial infusion of 5.75 gallons for dough-in to rest the beer at 95 degrees to suspend the enzymes in liquid and serve as a short acid rest. I then infused another 4 gallons to bring the mash up to 134 for a 30 minute protein rest. After about 30 minutes I pulled 4 gallons of a thick mash out for my first decoction. I took this up to a boil over 30 minutes constantly stirring. When I added this back in, my goal was 154, I hit 149. I let the mash sit for about 25 minutes before I pulled the 2nd decoction. This time I pulled 4.75 gallons of medium thick mash and took it to boil in about 15 minutes. Adding this back in got me to a mash temperature of 158. I let it sit here for 30 minutes until an iodine test showed complete conversion. At this time I pulled 4 gallons of very thin mash, liquid actually and brought to a boil, this made for my 3rd decoction, woops. This allowed me to mash out at around 165. I gave the mash a good stir after I added this final decoction back in and allowed to settle for 10 minutes. I've found that this really helps the grain bed run off well and help avoid stuck mashes.

I collected about 13 gallons to allow for a 90 minute vigorous boil to add some color and caramelization. During the boil I added 2 oz of Hallertau at 60 minutes and another 1 oz of Tettnag at 30 minutes. Once my boil was complete, I attempted a whirlpool in my boil kettle by stirring it for about 5 minutes and allowing the hot break / trub to settle. I was able to get the beer cooled to 58 in about 15 minutes and let it sit in my fridge overnight. My OG was 1.070 on a target of 1.054. My default efficiency is 65, this mash yielded 84%, I guess this is an Imperial Dunkel now, or a Traditional Bock.

The next morning the wort was at 48 degrees and I transfered to clean carboys, leaving the cold break behind. At this point I pitched my yeast starter, and I think I made a mistake. The starter was 2000 ml, 2 days old and at high krausen. The starter temp was around 65. I didn't chill it or decant the liquid off and now 18 days later, I taste a little bit more fruity ester than I think I should. The beer temperature has never gone above 55 and I am picking up fruity notes. I think I've learned a valuable lessen. Anyway, my gravity is around 1.020 now and I am just completing a diacetyl rest at 55, up from my fermentation temperature of 50. I will transfer this batch to secondary soon and allow to lager at 35 for a good 8 weeks. We can talk about it at a meeting in May or June, it should be ready by then.