Hi guys!
Just wondering how everyone out there avoids shocking the yeast culture when reducing the temperature of lager yeast from 21oc to 12-14oc for primary fermentation at this time of year?
I've got a temp controlled fridge (Outside in the shed) but this isn't going to be much use when the ambient temperature outside is 12-14oc anyway!!
Just wondering if anyone’s got any tips or will regular rousing help if the yeast does get shocked?
Fermentation Temp Reduction....Avoiding culture shock!!!
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steve_flack
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mysterio
You've got two options, both of which have given me good, comparable results. The benefit of cold pitching is up for debate.
First of all make a huge starter with about a gallon of wort. The big starter is critical and will let you get away with reducing the temperature quickly. With a pitchable vial you should get away without stepping it up but with a wyeast package you would probably want to step this up once or twice. Ferment the starter at room temperature until it has completed and then decant the liquid leaving behind the slurry. There should be about 1cm at the bottom.
Option 1 Warm Pitching: Cool your wort using your immersion or CFC to usual ale pitching temps (~20C). Pitch the starter slurry at the same temperature and then immediately set your fridge to the lager fermentation temps (~10C). I find this doesn't shock the yeast and they're happily fermenting away with in an hour or so and continue to do so at the colder temps. Getting down to fermentation temperature quickly is important as most of the fruity esters (which you are trying to avoid in a lager) are produced near the beginning of the primary fermentation.
Option 2 Cold Pitching: Once you've made your wort, cool it down to pitching temperatures (~10C). I do this by sealing the wort in a glass carboy and letting it chill in the fridge overnight (6 or 7 hours). At the same time, crash cool the starter to the same temperature OR below (do not pitch warm yeast). Then, decant and pitch the yeast slurry. A large starter is all the more critical for this method, and so is sanitation.
First of all make a huge starter with about a gallon of wort. The big starter is critical and will let you get away with reducing the temperature quickly. With a pitchable vial you should get away without stepping it up but with a wyeast package you would probably want to step this up once or twice. Ferment the starter at room temperature until it has completed and then decant the liquid leaving behind the slurry. There should be about 1cm at the bottom.
Option 1 Warm Pitching: Cool your wort using your immersion or CFC to usual ale pitching temps (~20C). Pitch the starter slurry at the same temperature and then immediately set your fridge to the lager fermentation temps (~10C). I find this doesn't shock the yeast and they're happily fermenting away with in an hour or so and continue to do so at the colder temps. Getting down to fermentation temperature quickly is important as most of the fruity esters (which you are trying to avoid in a lager) are produced near the beginning of the primary fermentation.
Option 2 Cold Pitching: Once you've made your wort, cool it down to pitching temperatures (~10C). I do this by sealing the wort in a glass carboy and letting it chill in the fridge overnight (6 or 7 hours). At the same time, crash cool the starter to the same temperature OR below (do not pitch warm yeast). Then, decant and pitch the yeast slurry. A large starter is all the more critical for this method, and so is sanitation.