Another wild yeast fermentation

[TimT]

I dunno.... don't the yeast just drift by and start living on the apples? At any rate I'd imagine it'd be pretty unpredictable either way, whether fermenting from yeast found on suburban apples, or yeast on country apples.

 

[Mutaneer]

Yeah, but when you think about an established orchard, the same yest that landed once upon a time ago has now populated itself on everything in the vicinity,
and no doubt other yeasts have come in, maybe taken over with time, but you would probably find that one/ two/ five dominant strains would be particularly abundant, obviously depending on other sources in the area.

All just a theory, and happy to be schooled by those boffins who know and study such things.
Maybe I should go back to uni and do this as a PhD topic....

 

[TimT]

Mmm but depends a bit on whether it's good yeast or not. Not sure whether a big orchard would help in that selection process - though I suppose it might make an attractive environment for all sorts of yeast, making it more likely that the 'right' sort of yeast is living on one of the apples.

 

[Kiwifirst]

Subscribed. What a fascinating thread.

 

[TimT]

Ha, what if this is the end of the thread?

Oops. Well now I've said that it clearly isn't....

Interestingly, this second attempt has started much quicker than the other, I guess basically because I didn't faff around for three days before putting it on the heat pad.

No sign of anything other than healthy yeast growth at the moment. (Watching yeast grow is a fascinating thing, btw - I often work in the study beside my ferments and got to enjoy at close range the start up fermentation of this year's batch of cider: it started with a ring of bubbles on the surface of the cider must, which quickly formed into a kind of donut shape. It formed a blanket a day after that, and then one or two days after that the blanket began to clear up and carbonation really began in earnest. Okay, maybe you had to be there....) It's clearly been spreading out from where it started this morning, when it was mostly close to the apple peel, whereas now it's covering most of the surface of the wort. The carbonation is slow (when compared with the sort of carbonation a domesticated yeast strain might be giving at this point) but steady.

Of course a mould could knock it out overnight but at the moment it's looking pretty good. I'll take it day by day.

 

[Kiwifirst]

Ha! Just told my boy to stop faff'ing around and get to bed. Then I see you using the word.

This is irrelevant to this scientific thread, I know.

 

[TimT]

So today it was different again - the action on the surface has turned into a white pellicle. At first I thought it was a kahm yeast, precursor to a lacto-bacilli activity. Now.... I'm not so sure. I looked around in the infection thread and found my way onto some brewing blogs for good measure.... now I'm more hopeful, it could very well be a wild yeast pellicle; apparently brettanomyces is in the habit of forming them, sometimes in the company of a bacteria. Carbonation still happening, bit slower than yesterday.

I risked a sniff last night (when it just looked like a more normal yeast); didn't get much - whereas my first attempt was generating weird chickpea smells, this one, if anything, just smelled a little peppery (and maybe I was fooling myself about that).

 

[TimT]

It's looking very much like the pellicle in photos two and three on this blog post.

 

[Midnight Brew]

How big was your starting wort Tim? Was it around 2L in the juice bottle? Did it take 4 days before that activity you described above?

 

[TimT]

No, I used a 2.4 L bottle but it's only a small amount in that bottle, maybe three quarters of a litre? It's in its third day now.

 

[TimT]

Day four; the white pellicle is dissipating and we're seeing a return to the kinds of surface action we saw on the first day - some carbonation, light brown colour. Still stuff going through the airlock at a leisurely rate. Very little sediment at the bottom so I'm not sure how much conversion is happening. I wonder if I made the malt extract too rich? It had a gravity of about 1.090.

 

[Kiwifirst]

I am going to give this a go, it looks like a lot of fun. I have three fejoia trees at the end of their fruit cycle and I have plenty of fejoias lying around. Don't have any malt or grain at the moment, so will do what you did first time round and use a bit of next weeks mash.
I am going to get a couple off the tree now and put them I a zip lock bag till next week, probably better than the ones on the ground.

 

[TimT]

Ooh! Feijoias! We made a nice fej wine last year, got to be careful with them though as I think they might be quite alkaline. Not to say yeast won't be living on them, I'm sure it will, but you might definitely want to add something to the wort to balance up the pH and tip it to the acidic side.

 

[Kiwifirst]

So would the best thing to do there, is to make up a starter and add the right salts, then keep adding and testing the alkalinity until it looks fine?

 

[TimT]

Yep, I think so, maybe mash the feijoias up a bit and mix them in so you don't get 'acid' parts of the starter and 'alkaline' parts? If I was starting from feijoias and had the right kit - brewing salts,and pH testers, I'd definitely do that. Also next time I try a wild starter I think I'd get several separate jars as an insurance policy, so if some starters fail others might still work.

 

[Kiwifirst]

Oh I wasn't planning on using the fruit only the skins. Do you think I should try and get the yeast started only with the fruit and some water, then add some malts?

Does sound like I need to get some ph test strips.

 

[Kiwifirst]

Ha!
Slightly off topic, but still on the wonders of yeast.

https://shine.yahoo.com/healthy-living/drink-night-without-getting-drunk-212500989.html

 

[TimT]

Oh. Right. Skins. Like with my ferment. D'oh!

http://upload.wikimedia.org/wikipedia/fi/c/c3/D_oh.jpg

Maybe the pH wouldn't change that much then? I assume the alkalinity mostly comes from the flesh.

 

[Mardoo]

Ha!
Slightly off topic, but still on the wonders of yeast.

https://shine.yahoo.com/healthy-living/drink-night-without-getting-drunk-212500989.html

That deserves its own thread!

 

[Kiwifirst]

That deserves its own thread!

It does, i'll do that