My wort is fermenting on its own

[jceg316]

On Saturday I made a California common. My yeast starter east ready so I couldn't pitch, had to crash the starter too as it was a 2l starter and not enough room in the FV for that. I come back tonight (Monday) ready to pitch and it's fermenting by itself .

Let's hope it's a nice sour beer...

 

[Ghillie]

Good luck with that, fingers crossed it’s a nice wild yeast!

 

[Cheshire Cat]

My experience is that it will be undrinkable but maybe you'll get lucky.

 

[user 18729]

It’s going to go one of two ways! Good luck!

 

[foxy]

On Saturday I made a California common. My yeast starter east ready so I couldn't pitch, had to crash the starter too as it was a 2l starter and not enough room in the FV for that. I come back tonight (Monday) ready to pitch and it's fermenting by itself .

Let's hope it's a nice sour beer...

Or it could be the yeast you tend to brew with regularly, I read an article about wine fermented with wild yeast, turns out it is mostly the house yeast hanging around waiting for their next sugar hit.

 

[The Baron]

Maybe funky in a good way if so crop the yeast for re_use

 

[jceg316]

wild fermentations have been 50/50 with me, some have become great sour beers, others I've had to pour down the drain. This is fermenting aggressively, loads of airlock action, looks like it came out the top of the airlock. Whilst this is nothing to go by in terms of if the beer will be good, it smells very earthy, kind of sulphuric and a bit medicinal.

 

[Cheshire Cat]

As I'm retired I can pick my brew days so I pick rainy days since it will reduce the risk of of external wild yeasts. Also rainy days mean not going out as much.

 

[jceg316]

As I'm retired I can pick my brew days so I pick rainy days since it will reduce the risk of of external wild yeasts. Also rainy days mean not going out as much.

I was unaware that rain would make a difference to wild yeast proliferating. What is the "science" behind this?

 

[Headlands]

They don't have umbrellas :)

 

[Wontigonk]

At a guess, rain helps suppress dust circulation?

 

[Cheshire Cat]

Exactly rain washes the air of airborne dust, yeast etc.

 

[MyQul]

On Saturday I made a California common. My yeast starter east ready so I couldn't pitch, had to crash the starter too as it was a 2l starter and not enough room in the FV for that. I come back tonight (Monday) ready to pitch and it's fermenting by itself .

Let's hope it's a nice sour beer...

This has happened to me a couple of times when I left the wort in my no chill FV longer than 48 hours. The beer has always turned out fine

 

[jceg316]

This has happened to me a couple of times when I left the wort in my no chill FV longer than 48 hours. The beer has always turned out fine

That's good to know. Was the beer sour or was the wort fermented with residual yeast in the fv?

 

[Gerryjo]

Or it could be the yeast you tend to brew with regularly, I read an article about wine fermented with wild yeast, turns out it is mostly the house yeast hanging around waiting for their next sugar hit.

One of my best brews was an Irish Red I had made for NHC competition and on bottling day it had a smooth white pellicle.Underneath was lovely so bottled.
After conditioning lively bottles but very tart as it had taken a wild yeast whilst fermenting.
Left it for a few months and wow what a lovely tart but sweet and complexed beer....

 

[MyQul]

That's good to know. Was the beer sour or was the wort fermented with residual yeast in the fv?

Must have been residual yeast (a thing Ive just learned from reading this thread) as the beer wasnt sour

 

[Slid]

I think there is a lot of yeast in most FV's as it is quite hard to shift it sometimes (especially if you are in a rush!). I always blame the very low SG's I get on yeasts like Belle Saison, which will go right down to 1.003 and which "take over" from the primary yeast.

 

[AdeDunn]

I've had the residual yeast thing happen a few times too, having used Belle Saison and MJ French Saison, it's makes for some very dry IPAs.... lol It can help to set aside FVs to use for certain yeast types to prevent this. Like I now have an FV only for use with Brett since I made an old ale using Wyeast old ale blend (contains Brett).

Wild yeasts where I live are, honestly, rank. During fermentation there's a very very strong smell of tobacco (which combined with the hops to give a very dank odour indeed), then that oh so lovely flavour of sticking plasters in the finished product...

 

[MyQul]

The way I nowsanise my FV prior to filling with wort should kill any residual/wild yeast. Fill the FV 1/4-1/3 full with boiling water and cover with cling film. The first 1/4-1/3 of the FV gets sanitised by the boiling water. The rest gets sanitised by the steam. I usually leave the FV overnight but you dont have to. Fifteen minutes or so with do the job

 

[jceg316]

@MyQul I always sanitise with heat where possible. However these are glass demijohns so possibly not the best idea. If I had an oven large enough to stick them in I'd do it that way.

The fermentation is dying down now and the airlock was smelling more like cloves, possibly due to underpitching. I'd imagine with a starting cell count of 0 there would be underpitching issues...