Where did my esters go?!

Hey Guys,

I have kind of a strange issue. So I brewed a hefeweizen recently which came out pretty well. I used Wyeast 3068 pitched from a 2l starter.

It came in pretty nice when all was said and done, a touch of banana and some other esters which were really only present in the aroma (slightly so in the flavor, but as I understand it, still in style).

It fermented until terminal gravity, aged for 1 week, and transferred to a keg. Carbed it up over 2 weeks, and kept the keg at about ~40. It had the ester profile for about ~2 weeks but the strangest thing happened. I drew a pint yesterday, and it had almost 0 ester aroma or flavor... it was gone.

The other thing I noticed is that the yeast dropped out of suspension completely (crystal clear). I was able to just invert the keg which solved that problem, but I didn't expect it to drop. The last time I this yeast it stayed in suspension almost the entire time I had it in the keg.

The banana ester, isoamyl acetate, is one of the quickest fading esters found in beer. Having a low initial concentration of this ester could contribute to the quick fade.

What yeast are you using? Hefe yeasts have very low flocculation, although with enough time at cool temps, most things will drop out of solution.

Mmmmmm Kristalweizen....

ColoHox said:

The banana ester, isoamyl acetate, is one of the quickest fading esters found in beer. Having a low initial concentration of this ester could contribute to the quick fade.

What yeast are you using? Hefe yeasts have very low flocculation, although with enough time at cool temps, most things will drop out of solution.

Click to expand...

I used Wyeast 3068. The description says overpitching can cause a loss of the banana ester almost completely... which is what I experienced.

I can't imagine I over-pitched with just a 2L starter though (for 4.5 gal @1.052).

Considering ester production is associated with yeast cell growth and division, and not fermentation itself, that is a large starter for a beer of that gravity.

One technique for encouraging ester production is to under-pitch. Although this can cause a whole variety of other issues.

Fermentation temperature will effect the amount of esters you get. Hefs should typically be brewed slightly warmer if you're looking for a more pronounced ester profile.