To extend this thread on a slight tangent, I heard that Brett will eat autolyzed yeast, if necessary, so what effect will storage of the harvested Roeselaere blend have on shifting the balance of the blend away from the original pitch/harvest yeast:bugs ratio?
Or is that geeking it to a microbiology level that a homebrewer should just ignore. With so much time invested in these sours, I am thinking I should at least ask!
Sorry for the hijack/diversion, Jim, but with the name of the topic, I thought it made more senses just go with this one further....
I "store" my mixed cultures at room temp in growlers. I decant the clearest beer and feed replace with fresh wort every 6-8 weeks. The starter wort is 1.030ish and has a big dollup of maltodextrin along with DME.
If you want to keep your Roselare going, just make a starter and pour in some from the keg/bottle (before chilling).
I expect that over time the sacch strains die off and leave brett and bacteria. If you're using an older culture, you can either pitch fresh sacch/brett, or just let it go. You don't really need a sacch strain.
I've also seen lacto viability drop off as the culture matures, so I've taken to pre-souring with a separate lacto culture for Flanders-style and quick sours (Gose), just to move things along. In traditional lambic, pedio does most/all of the souring anyway.
I kept my lambic culture going in a bucket by racking off and back on in the same day. The 2nd batch was exponentially more awesome than the 1st. I had to clean it when I moved, else it would still be going.