Stout Question

[Froggit]

Ok did my first AG stout on sunday, had a reasonable brew day but did struggle a little with my mash temperature.
I brewed with a Starter made from White labs WLP004 yeast and its been happily fermenting away in my fridge at around 60f since brew day.
Checked it a couple times yesterday and was getting a lovely caramel smell from my firdge and tasting after checking gravity it was sweet with chocolate, caramel and coffee notes but ending with a bitterness which i just thought (hoped) would clear during conditioning.
Gone to fridge today again everything seems tickerty boo but i get what i can only describe as a pear drops smell, very nice smell as i like pear drops but its also bordering on a chemical glue type of smell which also comes through in the taste.
Gravities have been sunday 1.08, Monday 1.072 and today 1.052.

Anyones thoughts on this would be appreciated, does everything seem ok, im just a little worried with the smell bordering on chemically!

I sterilize with chlorine but im very thorough with my rinsing afterwards so would assume it isnt that!

[Eric]

If it's fermenting as you describe, the chances of it having a thriving infection are small. Leave it well alone and stop worrying about chlorine, it'll no doubt create many more and different smells. With an OG of 1080, it could well be ready for drinking about Christmas.

[weiht]

dont be too bothered with the tasted though fermentation imo. Yeast (Some more than others) are known to put off certain flavours which some wld consider as off flavours during the early part of fermentation, which would be cleaned up and reabsorbed by the yeast towards the end of fermentation if the yeast is still active.. ie acetaldehyde, diacetyl sulphur. That is why many brewers practise raising the temperature a little to encourage the yeast to clean up the beer, or just let it sit longer even though its hit terminal gravity.

[gregorach]

"Pear drop" probably indicates isoamyl ethanoate or ethyl acetate. It's produced by yeast metabolism, particularly during the growth phase. If I recall correctly, production is enhanced by high gravities, low pitching rates, and high temperatures. I can't remember how the dissolved oxygen level affects it...

Your temperature looks fine, assuming that it's accurate... It's not clear if that's the ambient temperature of the fridge, or the actual temperature of the beer - if it's the ambient temperature then the actual beer could be several degrees higher. Your OG is also pretty high. How big was your starter?

If it really is isoamyl ethanoate or ethyl acetate, these are unlikely to be further metabolised by the yeast, but they can gas off during fermentation.

[Froggit]

Thats the ambient temp of the fridge, should i drop it a few degrees?
I hadnt planned on my OG being that high, just how it happend is through im guessing inexperience.
How do i explain the size of starter, 80grms DME with 800ml of water with the New yeast for 48 hours, imo it did look well!

[gregorach]

800ml is a bit on the small side for a starter, especially for such a strong wort - I normally go for a litre for a regular 1.040 - 1.050 wort when using my stir plate, and I'd usually recommend double that without one. Given the amount of yeast in a White Labs vial, you probably didn't get much growth at all - in which case a starter just stresses the yeast.

Changing the temperature isn't going to make much difference now - what's done is done. That temperature should be OK anyway. I'd say it's most likely down to a combination of high OG and too small a starter.