From UPS ...
Sent: Tuesday, 7 May 2002 2:28
To: Ackland, Tony (CALNZAS)
Subject: Re: [Distillers] fusels
Geez, why didn't you just ask if you wanted numbers!
This is for the Wyeast1056/whitelabs001 strain that is used for Sierra
Nevada's pale ale:
Ethyl acetate(mg/l): Amyl acetate(mg/l)
at 60F =16 0.5
at 68F 26 2.0
at 75F 53 4.0
Technically, ethyl acetate and amyl acetate are considered esters, not
fusels, but they act the same in the still. Fusel oils are formed by the
ferment of amino acids- not sugars. There are two types of fusel oils;
aliphatic and phenol. The aliphatic have a straight line structure and are
volatile- they have a warming alcoholic/solvent note with fruity tones. They
lead to definate harshness. Phenol types are involatile, aromatic alcohols
with a madicinal flavor. Lager yeasts fermented at the right temperature
(cold) form less than half the fusel oils an ale yeast does at normal temp.
(25mg/l against 70mg/l for an ale). All yeast start to increase fusel oil
production when sugar concentrations above 16% (sp.gr.1.065) are used.
Mutated and first generation (air-bubbled "lab-grown" yeast) tend to make
more than recycled yeasts do- hence the Scotch distillers use of second hand
yeast from the Dublin breweries). Does this help?