Tuesday, October 30, 2007

Brew day: Doppelbock? Schwarzbock? Imperial Schwarzbier?

Okay, so Sunday was a brew day, and Leah and I were planning on taking our first shot at a Doppelbock for our Christmas beer. With 20 lb. of malt and a target O.G. of 1085, it was by far the biggest beer we have planned (especially all-grain). While things didn't go totally as planned, I think I'm starting to get a better handle on all-grain brewing and I consider it progress. Here's the recap:

First, I decided to follow Dave Miller's suggestion and pre-heat the mash tun. Based on the resulting mash temp, I don't plan on doing it again. Between letting the strike water sit for twenty minutes and re-heating it to the mash temp, it probably added a good 45 minutes to the brew day.

I mashed in (1.25 qt./lb.) at 1pm at 171°F with a target mash temp of 158°F. Based on past experience I would've gone with 175°F (the suggested temp from the Green Bay Rackers website) but since I pre-heated the mash tun I decided to go with the ProMash strike temp, which has generally been too low for me. Turns out to be a bad idea as the mash ended up at 152°F. After 15 minutes the pH was at 5.1 so that was looking good. However, at thirty, when I stirred the mash, the temp was down to 148°F. I added some boiling water, but I didn't have much to add so it only brought it back to 152°F. Naturally I'm concerned that the beer won't have sufficient body, but what are you going to do?

During the mash rest, I heated up around seven gallons of sparge water to 168°F. The pH was at 7.1, so I added 1/2 tsp. acid blend. That only brought the pH down to 6-something so I added another 1/2 tsp. I forgot that pH was logarithmic, and I ended up bringing the pH down to 4.4. Oops. I can't find anything that says what happens when you sparge with water that's too acidic, but that may have contributed to the low efficiency that I achieved yet again.

At 2:08pm I started to recirculate. At 2:25 I started to collect the first runnings. I measured a gravity reading of 1072, which is a bit low (if I am to believe my fellow homebrewers at BeerAdvocate) but it's possible that the overly acidic sparge water was part of the problem. Also my sparge water cooled down to 162°F by the time I sparged (something to keep in mind next time).

I began to sparge at 2:35 and by 2:55 I had run off 3 gallons. I started the burner on the boil kettle as soon as I started sparging to carmelize the first runnings. The wort was at 1056. At 3:10 I had collected 4.5 gallons at 1041. By 3:20 the sparge water ran out. At 3:25 I had collected 6.5 gallons and the runoff was at 1030. At 3:40 I stopped sparging as I had collected what I thought was 8 gallons. Unfortunately, I was using a new keggle which required me adjusting my calibration sheet from the old keggle, and I think I screwed something up at some point because as I started the boil I realized I had actually collected close to 9 gallons. Obviously this makes it a little difficult to figure out what my sparge rate was, and this was something I really wanted to keep track of this time. D'oh.

I boiled from 3:40 to 6:25, boiling down from 9 gallons to 6 (I would've kept boiling down to 5.5, but we had company as of 5pm and I hadn't planned on being out there so long in the first place). My gravity reading at the end of the sparge was 1045, which would boil down to 1072 at 5.5 gallons. As it was, I boiled down to 6 gallons and ended up with a gravity of 1065.

Given the low O.G. and the low mash temp, I'm thinking this might come out too thin to be a Doppelbock. Given the generous amounts of Carafa I malt that I used, it's very dark so I'm thinking it might be considered a Schwarzbock. However, the low mash temps may make it too thin to be classified any kind of Bock, so perhaps Imperial Schwarzbier will be most appropriate. I suppose I won't know for sure until I try it.

In the meantime, I pitched at 70°F with the yeast cake from a 2L starter of WLP833 German Bock Lager yeast. I put the carboy into my chest freezer set at 55°F and fermentation had started by the next morning. Today I dropped the temperature in the freezer down to 50°F. Now I'll just have to wait and see how everything turns out!

So, in the end, it was a long day with some minor issues but things I can learn from. Mainly, I'm going to go with the Green Bay Rackers mash calculation plus 2°F for my strike temp and I'm going to go with 173°F for my sparge temp, figuring it will drop to 168°F by the time I actually sparge. I'm also going to add 3/4 tsp. acid blend per 7 gallons sparge water and see if that hits my desired pH range. In the meantime, we'll soon be off to Germany to visit Leipzig, Bamberg and Düsseldorf. Ja woll! I'll be posting pictures and brewery reviews when I get back. Auf wiedersehen!


Blogger Adam said...

Whoah! Now that's a full account. Thank you.

10:56 AM, October 31, 2007  
Blogger Ted Danyluk said...

Hey Russ,

It was so much fun meeting up with you guys for good food and homebrew tasting. You were telling me about all this at dinner, but now after reading this post...well, it must have been fairly stressful.

I just wanted to reiterate what what I was saying about about mashing. I try to eliminate as many variables as possible. Whether the tun is preheated or not, you are working with about 4 variables (tun temp, grain temp, strike water volume, strike water temp).

Fill the mashtun with the correct volume of strike water that is 5-10 degrees above the strike temp (depending on how cold the tun is...was it sitting in the house or outside somewhere?). Then, all ya gotta do is watch it until its precisely the right temp, and then carefully stir in the grains.

Stirring carefully, and adding the grains slowly ensures a good mix. Then after about 15 minutes give it a gentle stir by bringing some of the hot grains from the bottom to the top and "slicing" through the the bulk of grain-mass to get it all into suspension again. The "slicing" stir doesn't cause the mash to lose much heat, and I usually stir every 15-20 minutes.

I batch sparge now, and even when fly sparging, I've found that the sparge water needs to be about 175-180 in order to equalize at about 170*. I don't add any acids to the second batch sparge water, and currently my efficiency is fairly consistent at about 78%.

This method makes for a much easier and quicker brewday. I hope this helps in some way.

I really hope you guys have an awesome time in Germany. Be safe and sound. Cheers mate.


11:31 PM, November 01, 2007  

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