Harvesting wild yeast, fermentation restarted

Hello, this is my first post on the site, I have been a lurker for a while though. The concept of capturing wild yeast intrigued me and I went about to harvest some from fruit and flowers in New Orleans (home). I made a low sg wort around 1.030 and threw some Japanese plums and wild flowers from a field in the wort I also added no hops so i could really catch anything. The starter started fermenting within a day (made it on wednesday) and was pretty active for around three days, but then seemed to stop. Fast forward to yesterday when suddenly it restarted and fermentation seems to be increasing as the airlock is bubbling around every 18 seconds, compared to every 30 seconds yesterday. What could be happening, is this the succession of lactobacillus to saccharomyces? Also when it was fermenting earlier in the week it seemed to have a fruity aroma to it, now it seems to have no aroma.

1 day lag: sacch
1 week lag: brett

sweetcell said:

1 day lag: sacch
1 week lag: brett

Click to expand...

That is entirely possible- but it could have also been

1 day lag: lacto (strain that produces CO2)
1 week lag: a wild yeast- sac or brett (or other?)

Personally, I'd make a second starter that had ~10IBU's of hop power in it (a little diffucult to calculate on a smaller starter scale)-
add your bugs to that-
then pitch into a full brew and see what you get in a year!

Nah,one gallon batch to test it out.

Brandon_Doughan said:

That is entirely possible- but it could have also been

1 day lag: lacto (strain that produces CO2)

Click to expand...

maybe, but i my understanding is that it is unlikely that a heterofermentative lacto strain will take off in 24 hours at room temp. then again, who knows what a wild strain is capable of...

There are many different microbes in that starter, certainly not just Saccharomyces, Brettanomyces, or Lactobacillus. I would guess that the initial fruity smell was from Micrococcus. It is also likely that there are members of Pediococcus, Pseudomonas, Enterobacteriaceae, Streptococcus, Bacillus, and Clostridia in there. Of course, not the pathogenic species.

Active fermentation resulting in a drop in pH and/or ethanol production will kill off many of these microbes, but some will still contribute to the flavor profile and activity of the fermentation. The sugar composition, ethanol concentration, and hop presence of successive fermentations will select for species that may (or may not) make a good wild or sour beer.

If it were me, I would plate a sample from your starter and manually select some microbes to use in later fermentations, as opposed to just tossing the whole starter in. However, the latter process may produce something interesting. Cool experiment and great first post!

Very cool indeed, and a new spin on first posts asking "is my beer infected?"

I wanted to post an update on the little experiment. The starter had seemed to settle out and yesterday I decided to make a 2 litre starter for it. I made a 1.050 wort with 3 hop pellets of equinox thrown in (I have no idea what the IBUs are). I strained out the wild flowers and Japanese plums. The starter smelled really funky, kinda sour and like a real funky French saison yeast strain. I pitched it in at around 7pm last night and by 9pm there was visible activity. Fermentation seems to be flying by this point (3 pm the following day). The airlock smells faintly fruity but it may be hops. Based on the looks of it, it looks very yeasty. Anyway just wanted to update and let everyone see how its progressing.