Dominant esters since going BIAB

[FlatStrap]

g'day All, Since moving to BIAB I have noticed a sharp increase in the level of esters produced, especially early in the fermentation. these flavours definitely wane over time with a two week primary and I've also racked to secondary to try to reduce the esters. initially I thought it was hot side oxidation from stirring during the mash but leaving the dregs in the kettle and tasting the next day revealed a clean tasting sweet wort while the fermentation vessel had a strong flavour by morning after pitching a rehydrated us05 into a 1045 wort fermenting at 17 degrees. this didn't seem to occur at all when using extract(both liquid and dry) and steeping grains and with both dry and liquid yeasts leaving me with cleaner tasting beers from the fermentor than I'm producing now. in saying that, the all grain beers are certainly better after 4-6 weeks however they are never as nice straight from the fermentor and with Xmas looming I'd love to get them out and stored ready to go by then. any help would be appreciated, I chill and pitch at fermenting temp. My guess is that I need more oxygenating post chilling although I have never done much when brewing extract. Does the boil of the entire wort reduce oxygen perhaps.

 

[manticle]

Esters are a fermentation issue. If it's really esters you're noticing (describe the flavours), it's related to cold side.
If you were not doing full boils previously, it might just be lack of oxygen contributing (boiling deoxygenates the wort). Pitch plenty of healthy yeast into well oxygenated wort and ferment at cool, stable temps appropriate to style and yeast.

 

[hoppy2B]

Change yeast and go to Notto if you want a really clean beer. You'll get less hop flavour carry over though, so maybe increase your dry hopping rate to compensate, assuming you are brewing a hop forward style.

Or as Manticle suggested, a higher pitch rate may help.

 

[FlatStrap]

Having done a heap of research, I think the solvent like flavours I'm getting relate to pitching at too high a temp, something which has happened more since the immersion chiller struggles to get 20 odd litres to below 25 degrees at the moment and not oxygenating. I used to boil 7 litres and would chill that down in no time in a sink with ice. And then pour a heap of cold water onto that effectively oxygenating the resulting wort.
the flavours seem to wane with time, which makes the beer drinkable but lacking that clean fresh taste you want in summer. cheers manticle and hoppy 2b for your input.
one thing I'm starting to get with all grain is keeping things simple and doing the basics well. I think this my 5 the all grain and it's starting to

 

[michaeld16]

Go no chill then splash the buggery out of it when pouring into the fermenter is my thoughts