Thursday, 9 August 2012

Brew Day: German Pils

I picked up a couple of mercury thermometers at Science Supplies so that I could calibrate the various thermometers and temperature probes through the brewery.
As it turned out the PID temperature probe was reading about 2degC above the actual temperature, the mash-tun's dial temperature probe was close enough to be accurate, and the TempMate and cheap digitial thermometers were within about 0.5degC at most temperatures measured.

Insulating the converted kegs and silicon hose goes a way to help keep temperatures stable, however, the insulation on the hoses made them unwieldy and difficult to work with.  They were also impossible to clean by simply throwing them into the kettle filled with cleaner.  These little velcro straps (usually used to tie computer/electrical cables) seem to work well to hold the hose insulation in place, while also allowing it to be easily removed when required.

The little-brown-solar-pump decided to stop working mid-brew - again.  This time I disassembled it and cleaned it well inside - likely something that should be done every brew - given the amount of crud inside especially inside and around the shaft and housing.
Since the other little-brown-solar-pump is broken, I was quite relieved when this one worked again, not sure if it worked because it was cleaned or simply because it was allowed to cool down for 30 mins.  While they are cheap, I'm starting to think they are not worth the trouble, and will need to upgrade to a more substantial and dedicated brewing pump soon.

Although my fermenting fridge can only fit two fermentors, allowing for several weeks fermenting then at least four to lager, if I want to get lagers things finished before October, I have to get them fermenting soon.  For the moment I'll put this latest lager into the keg-fridge and then work out what to do after that - it's possible I'll lager each of the beers in the smaller corny-kegs, or even plastic-cubes, rather than in the fermentors like usual.

This German Pilsner has a very similar grain bill to the BoPils, however the German hops and Calcium Sulphate will likely give it more hop character.  Using the HERMS to step the mash temperatures will also be easier - and make the brew day shorter - than using decoctions.
German Pilsner
Estimated OG: 1.049 SG
Estimated Color: 3.4 SRM
Estimated IBU: 42.8 IBU
Boil Time: 90 Minutes

Pilsner (Best Malz) 96 %
Carapils (Weyermann) 4 %

Northern Brewer (11) (60 min) 17.4 IBU
Pearle (HG 12) (60 min) 9.3 IBU
Tettnang (HG 12) (60 min) 5.0 IBU
Pearle (HG 12) (30 min) (0.52g/L) 4.8 IBU
Hallertau (HG 12) (15 min) (0.42g/L) 1.5 IBU
Hersbruker (HG 12) (15 min) (0.42g/L) 1.3 IBU
Hallertau (HG 12) (5 min) (0.83g/L) 1.9 IBU
Hersbruker (HG 12) (5 min) (0.83g/L) 1.7 IBU
Hallertau (HG 12) (0 min, hop-back) (0.42g/L)
Hersbruker (HG 12) (0 min, hop-back) (0.42g/L)
Tettnang (HG 12) (0 min, hop-back) (0.42g/L)

Whirlfloc (Boil 15.0) (0.042g/L)
Yeast Nutrient (Boil 15.0 min) (0.042g/L)
Lactic Acid (Mash 60.0 min) (0.084ml/L)
Calcium Chloride (Mash 60.0 min) (0.17g/L)
Calcium Sulfate (Mash 60.0 min) (0.33g/L)

Mash In, Protien Rest (3.4L/kg) 55.0 C 15 min
Maltose Rest 61.0 C 45 min
Dextrinization Rest 70.0 C 45 min
Mash out 76.0 C 10 min

Bavarian Pils (BrewLab #5705) (18.75billion cells/L)

Pitch @ 8 C, Ferment @ 10 C
Since the Style Guidelines specifically mention Tettnang hops, the plan was to use them in place of Perle that were used in the Dortmunder.  However, even though they were picked and packed only a few months ago, the Tettnang smelled dusty and lifeless when they were opened, while all the other hops were nice and aromatic - so it's possible they were not picked, dried or packed in a way that helped retain their freshness.  Since I had them open and weighed I threw the Tettnang in early and late, but added the much nicer/fresher Perle at 60 and 30mins.

With the additional whole hops, there was quite alot of hop debris remaining in the kettle at the end of the boil (it smelled good too):

Unfortunately - or fortunately - will see when the beer is fermented - the little-brown-solar-pump decided not to turn itself back on right after the mash was ramped up to the Dextrinization Rest temperature, and took about 30 mins to get working again.  Since not all the mash was up to 70degC, I expect that the consequence might be a more fermentable wort than was planned, hopefully that will still fit with how a German Pilsner should be.

Other than the pump-failure the brew day went well, and for the first time on the new system, the volume into the fermentor was exactly as anticipated.  The gravity was within 1 gravity point of what was calculated and so it would appear that I have most of the parameters of the new system worked out.  I plan to narrow the mill-gap on the next brew, because it's possible that not all of the grain is getting crushed fine enough and so a small efficiency gain might be possible.

Letting the wort chill overnight before removing it from the break and pitching yeast might pose a small risk, however, pitching at low temperature should help minimize any yeast-off-flavours and also gives very clear wort into the fermentor:

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