Cropping yeast is something that is very common in commercial breweries because of a regular brewing pattern and the savings that can be made not having to pay for yeast every time you brew.
This was also something I was very familiar with in a commercial setting, whether that’s cropping from the bottom of a fermenter or skimming from the top. It’s something I’d never done as a homebrewer though, partially because the cost of pitching fresh every time is not prohibitive but mostly because my brewing is irregular.
Recently though I’d taken the effort to brew with a couple of yeast strains that I really like with one of them a strain that I can’t get again, both beers finished within a day or two of each other and with a holiday scheduled in I don’t have time to get more brews on so my best option is to crop for storage.
There’s a lot of information on the internet about this but I wanted something simple and easy for anyone to do.
Important things to remember
- Cleanliness is key
- Yeast washing
I can’t stress enough how important cleanliness is in all aspects of brewing, yeast cropping and storage is no different. I’m cleaning all my equipment with a chlorinated detergent, sanitising with a no rinse sanitiser and spraying everything with an alcohol spray sanitiser.
I washed my yeast in this instance, not in the commercial brewery sense where they lower the pH to inactivate bacteria but in the sense that cropping from the bottom includes a lot of Trub, hops and dead yeast cells, I don’t want that in my yeast culture.
It’s essentially a simple procedure:
- I racked off the beer from both fermenters to keg/bottle
- I swirled the yeast in the bottom of each fermenter to homogenise and make it easy to pour
- From one fermenter I poured the yeast slurry out directly through the tap, the other I poured out of the top, I put them both in the fridge and this is what I got (one of the samples)
- I then decanted the remaining beer from the sample leaving me with this.
- I then added 500ml of boiled and cooled water, homogenised it and returned to the fridge.
- As you can see there are three distinct layers, top layer is yeasty water, middle layer is clean yeast with a darkly speckled trub layer at the bottom.
7. I then decanted the water off to the drain, decanted the clean yeast layer into sanitised flasks leaving the trub behind and giving me this.
I’ll now store these in the fridge at between 0-2 degrees and then create a starter for them both when I’m back from my holiday and brew some more beer!