I’m planning my first sour soon. The grain bill consists of 2-row, Vienna, wheat malt and flaked wheat. Is there any reason to do a boil? I plan to keep the IBU below 5 so I would just want to kill off any unwanted stuff by heating the wort above 180F or so for 15+ minutes. What am I missing in my logic?
Is this a kettle sour or are you inoculating it with a culture of yeast and bacteria?
Inoculation. Planning to ferment with an undecided ale yeast for a couple weeks then pitching one of the combo products of Brett, lacto, pedio.
The logic is not accounting for DMS potential. Above ~180F, DMS will be created, which then necessitates boiling (for how long depends on your base malt). If you are going to do a no-boil brew, keep it between 150-170ish. Hot enough to pasteurize, cool enough to to create minimal DMS.
Boiling will also precipitate some of the excess proteins from the wheat, isomerize some small amount of alpha acids to balance the malt, and increase gravity with boil off. Some (or all) of these may not be necessary with a homebrew grist, although lambics produced with a turbid mash generally had long boils (2+ hours).
I’ve seen people follow no-boil techniques with sour beers and claim them to turn out the same as beers they boiled. I’ve never tried not boiling sour beer or tasted no-boil sour beer so I don’t have any personal experience to confirm or deny; however, some of the people I’ve seen talk about it I trust have a reasonable amount of experience brewing sour beer to know whether it changed anything about the beer.
I have brewed no-boil clean beers and they have a savory aspect to them I’ve seen some describe as mushroom-y and I wouldn’t say that is an unfair descriptor. I don’t know how that would change or disappear with souring and time. If you intend to brew a kettle sour here then maybe you’ll drink it young enough to still catch some of that character. If this isn’t a kettle sour I am personally not a fan of how those super low IBU sour beers turn out. Closer to vinegar than lactic sourness and brett in sour beers.
going this route you need to plan for months, if not a couple years of aging. Boil your beer as you normally would and up the IBU’s
I suggest that you sour first since some souring organisms will be inhibited by even 5 ibu. A yeast like Chico can tolerate pH in the mid 3 range with no problem.
Sour to the desired level with lacto, then pasteurize or boil briefly, then pitch yeast(s) and ferment.
I get more of a flour/bread flavor when doing no boils with wheat.