Lacto starter

[user 341102]

Brewing my second Berliner Weisse. Had good success last time using uncrushed base malt to create a lacto starter. This time, I saved a bunch of wort from the last brew (about 6 weeks ago) to serve as a starter. The starter was kept in my fermentation temp and followed a standard lager fermentation temperature schedule over the past several weeks. Although the wort was hopped (about 25 IBU), it had some sour aroma and flavor (and pH 4.15).

The plan was to split the starter for one yeast and one sour starter. So, I diluted to 1.035 gravity, boiled the wort, chilled, and pitched as appropriate for each starter (1 cup uncrushed Pilsner for the lacto). Only then did I remember the lacto starter was hopped. My question: will the hopped wort prevent lacto from growing in the starter?

I’m assuming it will sour with enough time. Just concerned it might not fit my plan to inoculate the full batch in 24h. Anyone else have a similar experience?

 

[VikeMan]

Only then did I remember the lacto starter was hopped. My question: will the hopped wort prevent lacto from growing in the starter?

Most likely. Some Lactobacillus species are more tolerant to hop compounds than others, but in general, I wouldn't get my hopes up too much. That said, I suspect something(s) will grow in the starter, but who knows what?

Also, is there a reason you're using malt as the source for your bugs? There are easier/better ways, like Goodbelly or Swanson L. plantarum pills. With malt, you will certainly get Lactobacillus (of unknown/variable species), but also other bacteria and possibly wild yeast.

 

[user 341102]

Appreciate the insights, VikeMan! I just prefer the low tech approach to souring. I don’t have the time or space to dedicate to traditional sour, so this is as close as I’m getting.

I saw a small 0.2 decrease in pH before my meter went out. The starter definitely smelled and tasted more sour this evening. I pitched anyway (before seeing this reply) and will check in the morning. Worst case scenario, I pitch some purer strain like you mentioned and finish the brew on Labor Day.

 

[user 341102]

About 7h post inoculation. Smell and taste of the wort are clearly sour from lacto. Didn’t open the lid for fear of oxygen exposure. Everything tracking so far. I’ll give it more time before progressing to boil, chill, and fermentation.

My takeaway is that some hopping doesn’t prevent all LAB from growing. I’d estimate the starter was about 10-15 IBU after I diluted the gravity. Perhaps I just selected a hop-resistant LAB strain? Good for this batch, anyway. I’ll try not to think too hard about how this affects future batches of “clean” beer, though

 

[user 341102]

Racked to a keg yesterday. The flat beer does taste more “wild” than “sour,” although there is some tartness. Could be the IBU or the short duration (24h starter plus about 12h in the kettle). I’ll follow up once the finished beer is ready to serve if only for my own records

 

[user 341102]

Racked to a keg yesterday. The flat beer does taste more “wild” than “sour,” although there is some tartness. Could be the IBU or the short duration (24h starter plus about 12h in the kettle). I’ll follow up once the finished beer is ready to serve if only for my own records

Finished beer tastes mildly sour with some lemon flavor. More complex than many commercial Berliners that rely on pitching a pure culture. Definitely some LAB present. I’m guessing Pediococcus and/or lacto brevis survived in the hopped media. Unfortunately, my pH meter seems to be dead, so I cant report an objective number. Oh, well. The taste is good if just a touch less sour than I’d hoped.