Infection?

[Rick_UK]

Hi Fellas

My Belgian pale ale has been in the FV for a week I took a hydro reading today and its only down to 1030 from 1060 - I expect it to get to at least 1015. My concern however, was that the beer had slightly astringent, vinegar smell and taste. Granted it is still fermenting so I don't expect it to taste as it should yet.

The yeast I used was some washed T58 slurry which had been in the fridge for about 7 months - hence my concern. I read a few threads on various forums where people had re-used yeast up to 12 months old without any issues so took the risk using this stuff. However, the slow ferment with the above taste makes me worried I should not have used it.

Any thoughts?

Rick

[oz11]

Did you make a starter for the yeast? After 7 months the yeast would not be in good health. Mr Malty gives the viability of 7 month old slurry at 10% and reckons on a pitching rate of nearly 1.2L for a 23L beer @ 1060

[darkonnis]

Aye, quite likely most of its starved to death and whats left that still lives wont be great. Gonna be honest, I'd be dubious about using it, I'd definitely test it in a starter first before chucking it in a high strength ale

[boingy]

Sadly, the vinegar smell/taste is something that is unlikely to diminish. You've done all the hard work so give the beer a chance to finish but you may want to lower your expectations.

I've had very mixed results re-using yeast. Now I use fresh yeast if I can blag some from a local micro and use dried the rest of the time. There are some genius godlike scientist types on Jim's who can seemingly grow stunningly good yeast from a single cell but I'm not one of them. Even with a stir plate I struggled to get enough yeast to pitch. I'd go through a couple of litres of wort and end up with about a quarter of the yeast I needed. I realised I was spending too much time trying to grow yeast and now enough time brewing.

If you are going to re-use yeast I'd suggest re-using it quickly and pitching more than you think you need!

[jonnyt]

I concur use slurry within a couple of weeks else make a starter. Also smell the slurry prior to pitching.

I tend to bung in two cups worth and to date my worts have gone off like train thus minimising infection risk

[Matt12398]

It's funny you post this because I kegged a beer made with T-58 last week and tried one of the few odd bottles last night which I filled at the same time and that has an almost astringent taste like you describe. I was half way between deciding if it's an infection or putting it down to a Belgian character smell and taste but it's not a nice beer at all. I did think it was almost vinegary.

[Rick_UK]

Thanks for the replies chaps. I did smell and taste the slurry and it seemed ok. I made a starter up of sorts almost as an after thought - I mixed the slurry with a solution of 100g dme and water which I left for 16 hours before pitching. Fermentation took a while to get going - about 24 hrs, but looked to be going fine after that.

It's more the vinegar smell and taste i'm worried about as I can pitch fresh yeast if the current crop has runout of steam.

It's still bubbling away slowly so I'll probably leave it to ferment out and see where its at in another week.

I'll be disappointed if it is infected as I was as careful with sanitation as ever - im wondering if it's time for a new FV? This one is getting a bit discolored and has a few scratches and scuffs on the inside which could have harboured bacteria?

Rick