I’ve read that different strains of lacto perform best at different temps, and that the higher the temp within range, the more sour it will get, preferably between 110 - 120F, especially if culturing raw malt. I am not culturing my starter from raw malt, just from WY5335.
To make a starter, I pitched a packet of WY5335 into 1/2 gallon of unhopped wort at about 118F, but an hour later, after checking Wyeast’s website where it said that their product’s temp range is 60 - 95F, I turned it down to 91F.
I want it good and sour, but clean. Based on your experience or knowledge using WY5335, do you recommend that I hold it at 91F until I pitch it in two days, or crank up the starter temp again, to say 112F? Currently I am heating it wrapped in a heating pad hooked up to a temp controller set to 91F with a 1 degree differential. I also purged the small headspace in the 1/2 gallon growler with co2, and tightly covered it with folded over sanitized tin foil.
I will split the starter in a couple days between two 5-gallon carboys each full of mash/sparge runoff boiled briefly and then cooled to 90F. I will use the sour worting technique and keep the inoculated runoff at 90F for probably 3 days… until it gets pretty sour, and then boil it with hops, chill, and ferment as usual with US-04 to make an Oud Bruin. Half will also get tart cherry juice concentrate at least mid-way into primary fermentation.