Washing yeast cultivated from dregs

HomeBrewTalk.com - Beer, Wine, Mead, & Cider Brewing Discussion Community.

Help Support Homebrew Talk:


Active Member
Jul 14, 2014
Reaction score
Mandaue City
So I recently attempted to cultivate the dregs from two bottles of Chimay (I know, I know, some sources say the bottle conditioning yeast strain is not the same as the primary strain - wanted to try it anyway). I started with a few mL from the bottom of two bottles (one dubbel, one tripel) that were as fresh as I could find them and added the cakes to about 400 mL of 1.036 DME wort (I added a few grams of bread yeast during the boil in the hopes that they would lyse and provide some needed nutrients). I bubbled some oxygen up through it for about sixty seconds, too, and gave it some intermittent shakes over the next few days as I don't have a stirplate. Left the top loosely sitting on the container and left it sitting in my cold room, which I keep at around 22C.

So five days later, some fermentation has definitely occurred - there was some bubbling going on, and a nice (though not terribly) thick layer of cake is sitting on the bottom of the beer. I tasted a few mL (picked up through a sanitized syringe) - very reminiscent of Chimay Tripel, with lots of pineapple and a few spicy notes. It's a little tart, but not terribly tart.

The tartness made me think maybe I introduced something else along the way, however. Could I do an acid wash or a ~30ppm chlorine dioxide wash to ensure the only living thing I have in that cake is yeast, or is there something about the process of harvesting yeast (the weakness of the cells, the likelihood of mutation after sitting in the bottom of an alcoholic bottle for so long) that suggests that washing would be detrimental at this stage? If not, should I do another step up first, or should I do the wash now before I step it up?