Cultivating sour yeast.

[Grealish]

I have cultivated a healthy amount of yeast from a bottle of Gueze that I bought in Waitrose. I'm a big fan of Andrew Morton's recipes and he recommends adding the dregs of sour beers to bought sour yeast. Is there any reason I can't just grow the yeast I have to full size and pitch that?

 

[strange-steve]

What gueze was is?
The reason is that what you'll have there is actually a blend of numerous different sacch and brett strains plus various bacteria strains such as lacto and pedio.
So if you culture that up it'll throw off the balance of cultures in an unpredictable way. This is the same reason it's not recommended to make a starter with sour blends.
If you want to make a lambic then just get a commercial sour mix such as Wy3278 or WLP655 and you can add the dregs from your gueze to maybe add a little complexity.

 

[Grealish]

Aaah, that makes sense. I'll ditch it then.