Brew # 7 - German Lager

Paul Middleton -

Ingredients

  • 2x Morgan's Master Malt Extra Pale Ale malt extract 1.5kg (each)
  • 400mL liquid rice malt syrup
  • 375g Munich malt
  • 35g Tettnanger hops (3.7% AA) (Boil)
  • 15g Hersbrucker hops (3.5% AA) (Aroma)
  • 5g Irish moss powder
  • 3x SafLager W-34/70 dry yeast (11.5g)

Targets

OG: 1.050 - 1.054
FG: 1.014 - 1.018
ABV:  4.2 - 5.25%

Method

Brew day

  • Fill basin/bowl with hot tap water and add one tin of the LME to soften (turn occasionally)
  • Fill stockpot w/ 12L cold filtered water and start to heat
  • Boil 1.5L water in kettle
  • Empty one of the Extra Pale Ale LME tins into the pot and rinse tin with boiling water (try to limit the extra water, if possible)
  • Stir so LME doesn't stick to bottom of pot
  • Tie one end of the grain sock closed, fill with grain, then knot the bag closed, allowing as much room as possible for the grain to move
  • Tie the grain sock to the stockpot handle
  • Fully immerse the grain bag in the wort to steep
  • Continue to raise temp of wort until within the 49-77C range and steep the grains for 30 mins at this temp (hit 49C at 11:38)
  • Remove the grain bag, giving it a light squeeze, but do not fully drain the bag (removed at 12:08 - temp 75C - turned the heat down slightly at the end to assure it didn't exceed 77C within the 30 minutes)
  • Cover the stockpot and bring to the boil
  • After 10mins at boiling temp, add first hops (Tettnanger)
  • Boil for 50mins (watch for boil over) - the new stockpot has enough head room to make this unlikely if I leave a 1cm gap in the lid
  • I brushed the hop "tide mark" on the sides of the pot back into the wort a couple of times
  • Add 1/2 - 1 tsp Irish moss to boil for last 10 mins
  • Add second tin of LME to hot water to soften
  • Turn off heat (I'm using induction cooktop, so I just 'turn off')
  • Add final hops (Hersbrucker)
  • Add liquid rice malt extract and second tin of LME, stirring continuously
  • Aroma hops, rice extract and LME are allowed to sit for 15 mins to pasteurise, but do not boil
  • In the meantime, put ~5-10l of cold water in a sink (sealed with plug) and add two bags of ice
  • Whilst the second ME addition is standing, add 10L cold filtered water to sanitised FV (aiming for a total volume of ~22L as some of the wort water would have boiled off)
  • Place stockpot in ice bath in sink
  • Stir gently, no splashing, ensure no water drips in wort especially water from the ice
  • Once wort and FV water temperature equilibrium is ~25C, pour wort into FV using sanitised funnel and filter mesh (I noticed using the funnel and mesh filter gives really good oxygenation - lots of bubbles in the wort)
  • I had to add a further 1L of cold filtered water to reach 22L total wort
  • OG reading with hydrometer was 1.045 @ 24C (~1.047 with temp adjustment)
  • Aerated wort in FV by sloshing around, then place in the fridge

Yeast prep and pitching

  • Boil 500mL of water, pour into sanitised container (jar), and cover (Glad Wrap)
  • When boiled water temp cools to < 25C, sprinkle dried yeast on top - do not stir - cover
  • After 15 mins, gently stir without splashing and place in the warm fridge for min 15mins
  • Once wort and yeast temp have equalised (ambient temp), add 500 - 1000mL oxygenated wort to the yeast using the butterfly valve attached to a sanitised spout and length of vinyl tube
  • Cover yeast starter and place back in fridge

Fermenting

  • Reduce temperature of the fridge with wort and yeast starter to ~12C (0.8C per 90 minutes x 12)
  • Oxygenate the wort (slosh around some more)
  • Swirl the yeast to suspend the pitch in the liquid, then pour into wort
  • Close the fermenter, making sure the dip tube ends up hanging under the float so you can get the beer out
  • Leave it alone

Diacetyl rest

  • Starting on day 5 (Thurs 13/8), raise the temp by 3C per day (0.5C/4hrs) until it reaches 19C
  • Leave (from Sat 15/8) for 4-7 days

Lagering

  • Reduce temp by 3-4C per day for ~5 days to a temp of 3C (0.3C/2hrs x 12 x 5 days) - started 6pm, Weds 19th Aug (started a bit early as I need to drink on 30th)
  • Note: removed the collection bottle, emptied, and re-fitted (butterfly valve closed) at the same time I started temp reduction
  • Took a hydrometer reading - 1.012 @ ~5-8C (1.010 with tenp adjustment)
  • ABV = 5%

Coming next...

  • After a week at this temp, transfer to keg, carbonate, and drink

Improvements for next time

  • Two grain bags will mean the grain can circulate a bit better
  • Finer mesh on funnel filter - still lots of solids making it through to the Ferm'us
  • ATTACH A PRV!!!
    After a few days, I attached a PRV and didn't think anything was happening until I realised the needle had flipped round the dial. I don't know what the pressure was, but I was releasing with the spunding valve (slowly) for at least 30 seconds, so I reckon it was > 35PSI, which is the max rating for the Ferm'us.
    Next time - attach a PRV at the start if using the pressure kit.