My last brew was a sour beer, my first ever attempt at a sour lager. I used 4# of Weyermann Vienna and 2# of Weyermann Light Wheat, mashed in with 6 quarts of water to reach a saccharification temperature of 155F. I put the mash tun inside a sleeping bag overnight, and by the next morning it was down to around 120F. Perfect temperature for inoculating with lactobacillus.
Lactobacillus delbrueckii naturally occurs on barley husks, so I tossed a handful of crushed grain on top of my mash. After covering tightly with saran wrap to ensure that no oxygen was present to favor spoiling bacteria, I put the tun back in the sleeping bag for 24 hours to allow it to sour. The next day I was greeted by a very nice sour smell in the mash, almost like sourdough. Not quite as sour as some previous beers I've made, but not too bad.
I decided to brew a Gose-type beer, but without adding salt. I hopped the brew to about 10 IBUs and ground half an ounce of whole coriander seeds in a coffee grinder. The ground seeds went in for the last ten minutes of the boil.
The chilled wort didn't smell nearly sour enough, nor did any of the coriander come through. But I had a huge blowoff the next morning, the first time I think I've ever had a lager brew blow off before, and the gas coming from the airlock had a very definite, strong coriander seed aroma. It almost smelled like freshly baked Kranzbrot.
Tomorrow I'll transfer it to secondary after I brew my next sour base for the raspberry beer I'm planning on making. And the potato beer and sweet potato beer, after about three weeks of cold conditioning, are finally out of the refrigerator. I'll try to bottle those soon, along with the rye beer that needs bottling.