Saturday, 13 February 2016

Yeast washing

Fresh liquid yeast is great. I think it makes for better beer and certainly the beers i have made with liquid yeast have been better on the whole than those with dried yeasts. But there are some drawbacks. 
1) liquid yeast is much more expensive than dried - at nearly £8 for a phial or smack pack. 
2) the yeasts are imported from California - which means that they rack up a lot of air miles. This seems really disproportionate seeing as many of the yeasts I use are English, Belgian and Scottish - from about 250 miles of where I live. Brewlabs at Sunderland University has a limited number of UK yeasts available - but there is nothing in the EU that is anything like Whitelabs or Wyeast. 

So for both cost and environmental reasons it makes sense to re-culture yeast. It's also a useful back up to have a store of dormant yeast in the fridge ready to go if your planned yeast fails. 
I harvest yeast from the previous fermenter. there's always a layer at the end, a yeast "cake" that is left after the beer is racked off. I add some cooled boiled water to this and then pour off the sludge to some sanitised jam jars. Then once this has settled I pour the liquid from these into a smaller jar, leaving the solid trub. 

I seal the jars tight and keep these in the fridge. These can be woken up before using to make the next beer by adding them to a sugar solution, or a wort. 

In general I add 100g of sugar to 1000ml of water - then add the saved yeast. See the results below which are the two yeasts for my next brew. They were ready to go after 48hrs! 
  






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