Harvested Yeast Starter For Bottling Smells Like Vinegar

[Bobo1898]

I've seen plenty of posts regarding someone's yeast starter smelling like vinegar. Seems more often than not, it sounds like if the liquid is decanted, there is not as much concern.

However, these posts are for making a starter to ferment an entire batch. I made a yeast starter to propagate yeast for bottling and I'm getting some of those aromas. Would it be a bad idea to pitch this yeast with my priming sugar?

This yeast is 2nd generation (batch wise). Made a single a while back with 3787/530, harvested yeast from that and used that to make a Belgian Dubbel.

I made the dubbel back in May. Harvested yeast (around 68F) during fermentation and sealed away in the fridge to use for bottling. I ramped the temp up and the beer got as hot as 84 over the course of 7 days. Wanted to get as much of this yeast out of suspension because it fermented hot, so I lagered it. It ended up sitting for six weeks before I've been able to get around to bottling. I pulled a sample of this before transferring to a keg (which I bottle from) and it tasted great. Note--even when bottle conditioning, I use the keg as a "bottling bucket."

My harvested yeast has been sitting in the fridge since May so I decided that it would be a good idea to make a small starter---500ml with yeast nutrient---to make sure the yeast is good to go. I threw it on the stir plate and activity started fairly quickly. Normally my starters run two to three days, on average, before all krausen or activity drops (if I'm lucky to see it). This thing sat for 6 or 7 days and still had some visible krausen (thin)--all around the edges and around the vortex/funnel. I figured this had been on there for too long and wanted to take it off before any more/other bugs get introduced. So I took it off the plate, poured into mason jars, topped with distilled water and crashed.

They've been crashed for a week and I decanted this morning because I want to bottle today. After decanting, I smelled the yeast and the little starter beer that was left with it and got vinegar with a hint of oxidized beer. I have not tasted it yet but may run home for lunch to see if it tastes like vinegar.

With me pitching for priming purposes, should I have any concern with this harvested yeast ruining my batch? My dubbel is around 8% ABV. Would hate to alter the trajectory of this beer.

 

[lumpher]

You have some experience brewing. If you think it's not good, if I were you I wouldn't risk the time or money spent on a new batch. Especially sitting for a week, I don't think I'd risk it.

 

[lmaa]

Doesn't alcohol turn into vinegar when exposed too long to air?

 

[ba-brewer]

@Bobo1898 If there is a vinegar smell from a starter decanting will not help.

@lmaa Acetobacter turns beer/alcohol to vinegar.

 

[RM-MN]

If your starter smells and tastes of vinegar you have an acetobacter infection. If you use all or any part of the starter with an acetobacter infection, it will affect the rest of the batch and you will have many bottle of malt vinegar. Best thing to do is dump it and thoroughly clean the vessels this starter was in before you use any of them for brewing purposes.

Why do you think you need "bottling yeast" for your dubbel? It is likely that your beer has sufficient yeast for bottling and if not there is no reason you can't use a different yeast for that purpose.

 

[Bobo1898]

Yep, I ran to the store that day and bought new yeast. Dumped the vinegary stuff down the drain.

Why do you think you need "bottling yeast" for your dubbel? It is likely that your beer has sufficient yeast for bottling and if not there is no reason you can't use a different yeast for that purpose.

@RM-MN after fermenting hot---upwards of 84 (gradual rise)---I lager the beer after terminal gravity for 4-6 weeks. Aside from most of the yeast being dropped out of suspension via lagering, I'd rather not referment in the bottle with yeast fermented that hot. So I usually try to pitch harvested yeast (from early in fermentation when the temp is lower), or new yeast, if needed---like in this case.

 

[VikeMan]

Doesn't alcohol turn into vinegar when exposed too long to air?

No. Not without help from microbes.

 

[fluketamer]

yeah what they all said throw that yeast out. i made 3 gallons of vinegar stout repitching a vinegar tasting slurry.

i always taste the supernatant before repitching - if it taste like flat dilute beer repitch. if it tastes yeasty repitch. if it taste a tiny bit tart you can repitch with caution . some yeasts taste more tart than other (diamond lager) . if it tastes or smells like vinegar throw it out.