Unusual Foaming/infection Day 6

[felon]

Hi all
I have never had an infected brew before. I have been brewing for about 7 years now. I recently failed to clean out one of my fermenters for about 10 days after I kegged a batch. I noticed a hazy/powdery looking film starting to grow on the surface. I needed this fermenter for a new batch. Being very paranoid, I gave it a very thorough clean with a very strong solution of PSR, followed by a soak with a cup of domestos in 5L of water ans shaken around every few minutes for an hour. Then gave it another clean with PSR and a good rinse with tap water, and then 2L of boiling water shaken around for several minutes. I thought this would have killed anything.
I don't normally reuse yeast from previous batches but had nothing on hand this day. I kegged a 20L batch at about midday from a separate fermenter which was brewed with whitelabs WLP001. After I cooled my next double batch (approx 2.30 pm) I drained about 5L from my kettle onto the trub from the previous batch and gave it a swirl then dumped this mix into my (what I thought was sanitized) fermenter. Note: the cling wrap was not disturbed from the previous batch allow airborne matter in. Fermentation commenced as expected in a temp controlled fridge at 18 deg c. Everything looked normal until day 5 when I noticed the krausen was getting rather large. The next morning (day 6), the foam was overflowing from the fermenter. Highly unusual given that this was a 43L batch in a 60L fermenter. SG was reading 1.010. It should have been finished. Tasted the sample and it tasted rather grainy and maybe a little sour (not sure if i am paranoid). I dropped the temp of the fridge down to 16 deg to try and slow it down but have never had this problem before. Checked the SG the next day, still at 1.010 as expected.
The Krausen should be collapsing back in, not overflowing at this stage. I intend to give it 14 days in fridge as usual but I think this batch might be the first one I tip out.

 

[Ross]

No problem that I can see.... Lovely large healthy krausen from what can be seen - The result of a nice large yeast pitch.

Cheers Ross

 

[felon]

I knew it was going to be a large pitch rate, but i was expecting that much krausen at the 24hr mark, not at day 6 when the sg was 1.010.

 

[felten]

There are a lot of stories out there about wlp001/1056/us05 turning into a major top cropper after repitching, or it could be from using the entire volume of trub from a previous beer.

edit: im slow

 

[felon]

I thought the trub from 21L wouldn't get too carried away when 43L dumped on it.

 

[Ross]

Your main potential problem (unless the yeast was already infected), is if you didn't keep fermetation temperature under control with such a large repitch. You really need to keep the fermentation temp under control. If you did all should be fine. A good top cropper will often sit like that for ages even after the brew is completely finished.

cheers ross

 

[felon]

Thanks Ross, temp control is fine. The previous batch tastes great, so i don't think it's a yeast problem. I have had the temp down at 16 deg for 36 hrs now and although its not pushing on the clingwrap hard, it hasn't collapsed in on itself. It just seemed very vigarous for so late in the fermentation. Must be a very good top cropper then.

 

[flano]

having a similar thing happen to me at the moment.
2 brews done at the same time with 2 different yeasts ( same origin - but different shelf dates )
Both done last Saturday , one is almost clear on top now...the other is still powering with a 4 - 5 inch good krausen.
Only early days yet I guess.
I thought one had stalled.

so you do not need the krausen to completely dissapear before kegging/bottling??