Monday, 6 August 2012

Brew Day: BoPils

Ideally I'd like to get each beer into the fermenting fridge as soon as possible, however the exact schedule is dictated somewhat by the yeast propagation process, which takes some time since each yeast strain is propagated from a slant into a 4.5L starter.  Usually I'd repitch the rinsed slurry into the next batch of beer but this year a new yeast and starter will be used for each.
Fresh yeast slants were made for each strain and stepped into a 100ml starter, up to about 600ml and then to 4.5L.  The first two steps take about a 24 hours, which should be more than enough time for the yeast to grow as much as it's going to.  The last 4.5L starter is grown on the stir plate for 24 hours, before being left to complete the fermentation process and settle out, which usually takes another 24hours.  As the yeast starts to settle, the batch of beer it will be pitched into is brewed.  That way once the beer is brewed, chilled and ready for the yeast to be pitched, the yeast will have finished fermenting the starter, settled to the bottom of the flask ready for the spent starter beer to be decanted.

The plan for this Bohemian Pilsner is to brew it to a slightly lower gravity, but with significantly more hops (quantity rather than IBU) and additional malt-balance than last years.  The hop character should be enhanced by using Saaz in all additions, including a number late in the boil, however most of the hops (09 Czech Saaz) are a little older and so using extra is probably a good thing anyway.
Estimated OG: 1.054 SG
Estimated Color: 3.5 SRM
Estimated IBU: 42.8 IBU
Boil Time: 90 Minutes

Pilsner (Best Malz) 94 %
Carapils (Weyermann) 6 %

Saaz (09) (First Wort Hops) 15.8 IBU
Saaz (09) (60 min) 14.3 IBU
Saaz (09) (30 min) (1.25g/L) 6.9 IBU
Saaz (09) (30 min) (1.25g/L) 3.6 IBU
Saaz (HG 12) (5 min) (1.25g/L) 2.2 IBU
Saaz (HG 12) (0 min, hop-back) (1.25g/L)

Lactic Acid (Mash 60.0 min) (0.084ml/L)
Calcium Chloride (Mash 60.0 min) ((0.033g/L)
Calcium Sulfate (Mash 60.0 min) ((0.042g/L)
Lactic Acid (Sparge) (0.0001 ml/L)

Mash In, Acid Rest (3.6L/kg) 35.0 C 30 min
Decoct 30%
Protein Rest 53.0 C 15 min
Saccharification 63.0 C 35 min
Decoct 20%
Saccharification 71.0 C 35 min
Mash out 76.0 C 10 min

European Lager II (Wy2247) (18.75billion cells/L)

Pitch @ 8 C, Ferment @ 10 C
The decoctions added a significant amount of time (about an hour) for each step (they were used), so it was skipped at the Protein Rest so that the (modified) malt was not held too long.

Decoctions were taken such that they were comprised of the thick (mostly grain) portion of the mash:

Using the a special (ie: broken) decoction jug:

Which actually works well, because the mash liquor drips from the bottom of the jug back into the mash while retaining the grains:

Each decoction volume was chosen so that when it was returned to the mash it would bring the temperature up slightly below the next step temperature,  with the adjustment made via the HERMS.  The decoction was heated to Saccharification temperature (65 to 70 deg C) and held for about 15mins:

Before boiling for about 10 mins:

A little care needs to be taken when heating the decoction - which was done on the stove, in an 11L pot - so that the grain does not stick and burn onto the base of the pot (hence the spoon in the pictures above).  Once the decoction was at boiling point, it did not need any additional attention:

With a portion of the mash removed for each decoction, the mash tun looked a little empty:

As mentioned earlier, while the overall IBU's should come in somewhere about 43, there is actually a fair weight of hops in this recipe:

As the wort was drained/pumped from the mash into the kettle, it was time to add the first of the hop additions (First Wort Hops):

As the last hop addition was added, the plate chiller and hoses are sanitized by running boiling water from the HLT through them:

Then the kettle is drained into the hop back, pumped from there through the plate chiller into the fermentor, into the fermentor the wort temperature was about 14degC:

Unfortunately - since I was making spaghetti bolognese at the same time - I forgot to add both the Whirlfloc and yeast nutrient.  The yeast nutrient can be added (with a little bit of boiling water) directly to the fermentor when the yeast is, but hopefully the lack of Whirlfloc will not be too bad, into the fermentor the wort didn't look too bad:

The fermenting fridge already has beer in it, so I had to borrow the keg-fridge over-night so that the wort could be chilled  ready for the yeast to be pitched in the morning:

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