ESVA fermentation profile

[GrahamB2]

Made a first attempt at the ESVA recently, and used the recommended Commercial Coopers ale yeast, using 5 CPA stubbies.

 

After 7 days, the fermentation (via airlock activity) had slowed considerably, but the SG reading was still 1030.

 

Decided then to add one of the yeast sachets, which then recommenced consistent airlock bubbling. After another 7 days the SG reached 1010, which was quite unexpected.

 

This means the ESVA clocked in at around 8%, mainly thanks the the sachet yeast.

 

I was under the impression that the cultivated yeast should attenuate a brew to a lower SG than the packet yeast, but may not always be the case.

 

Cheers

[Kearnage]

Graham,

 

I thought I'd been 'sleep posting' when I read this - exactly the same thing happened to my ESVA. At day 7/8 all signs of fermentation had stalled with the commercial PA yeast, at an SG of 1030 (stable over 2 readings). I threw in the sachet yeast, fermentation took off again, and I ended with an FG of 1010.

 

Next time I do a high gravity brew with the commercial yeast, I think I'll start with a pale ale or similar, and re-use the yeast from that for the ESVA. It always seems to really take off second time around.

 

Cheers

 

Dan

 

[PB2]

[rightful] Ignore the airlock [rightful]

 

The symptom you describe is an indicator of insufficient healthy yeast pitched at the start.

Grow the starter up for a day or two more prior to pitching.

 

Yep, second time around yeast slurry will contain shed loads more healthy yeast cells [wink]

[GrahamB2]

Thanks for the replies.

 

My yeast starter, when pitched, was 3 days old. It had a 10mm head of foam in the 1 litre bottle, and the sealed glad wrap covering had formed a constant "balloon shape", so I assumed that the cultivated yeast was ready.

 

So, PB2, are you saying that another 2 days or more would have avoided my problem?

[PB2]

That sounds quite active. Maybe an extra day or two with regular agitation will help the cause.

 

The yeast population, in suspension, grows exponentially to a point where it reaches a plateau.

 

With obvious fermentaion activity happening (foam, cloudy and lots of tiny bubbles rising) the population in suspension is maintained while healthy yeast (and not so healthy) will be sedimenting out - this will increase the overall population of yeast in the vessel and in turn available for pitching.

[Kearnage]

Would any advantage be gained from making a starter (for higher gravity brews) using light dry malt instead of (or with) dextrose?

[PB2]

A malt based wort is an advantage when the yeast has gone through more than one fermentation (primary and secondary) or more than one step-up, prior to pitching, is planned, eg. 100ml then 1litre then 10litres.

 

Having said that, LDM can only help rather than hinder, all my mini-worts are malt based because I have it handy [biggrin]