Berliner Weisse – kettle sour

Brew

Hops

Hop50min10minWP 75C
Taiheke5g10g35g

Grain

  • 3.0kg Pilsner Malt
  • 2.5kg Wheat Malt
  • 0.5kg Vienna Malt

Yeast

US-05 2 packets

Water Treatment

1/2 teaspoon Cal Chl, 1 teaspoon Cal Sulphate, LA88% to pH around 5

Boil Additions

1/2 whirlfloc and 1/2 yeast nutrient at 10 minutes left

Brew

  • Mash in at 65°C with 18L, rest for 60 min at 65°C.
  • Mash out: 10 min at 75C
  • Sparge with 15L at 74.9°C
  • Preboil size 27L
  • Boil time 60mins
  • Postboil size 24L
  • Fermenter volume 23L

Fermentation

Fermenting at 18C for primary fermentation period, then to 21C for diacetyl rest.

Fermenter Additions

N/A

Carbonation

N/A

Bottled

N/A

Final Volume

N/A

Notes

My first attempt at a kettle sour having had mixed results with Philly sour yeast. The process was the usual mash in, boil, ferment but with an intermediate step after mash for the kettle souring. Produced wort with both mash and sparge water pH around 5.5 with a few drops of LA88%, and brought wort to boil for 10-15 minutes to ensure no undesirable bacteria. Also sterilized counterflow chiller during this short boil. Reduced wort to 38-42C. Once at temperature, I adjusted pH to 4.5 using LA88%, then added the contents of ten tablets of Lactobacillus Plantarum (Inner Health brand from Chemist Warehouse). The L.Plantarum can tolerate lower pH and so dropping to 4.5 leads to cleaner, faster souring without compromising flavour. I purged the Grainfather with CO2 then clamped the lid (sprayed with sterilizer), and placed cling film (also sterilized) over the hole. I set the temperature to 38C. After 24 hours pH was 3.8 and after 46 hours it was 3.6. Satisfied with 3.6, I brought the wort to the boil for a further 50 minutes and added hops, yeast nutrient and whirlfloc. I’ve gone with Taiheke 50g not for bittering, but to enhance flavour. I opted for US-05 as a good work horse ale yeast with a tolerance to lower acidity. However opted for 2 packets to compensate for impact of lower acidity on the yeast performance.