🥃 Think those fruity whisky notes come from the barrel?
They’re already there in the wash.
During fermentation, yeast produces esters — flavour-active compounds formed when alcohols and acids combine. These shape the fruity backbone of a spirit long before it ever meets oak.
Here are some of the key esters found in whisky, and how they form:
🍐 Ethyl Acetate (ethanol + acetic acid) – Pear drops, crisp apple. One of the earliest esters to form — bright, volatile, and essential to fruity new make.
🍌 Isoamyl Acetate (isoamyl alcohol + acetic acid) – Banana foam, estery lift. Yeast strain and fermentation temperature have a big influence — longer, warmer ferments often bring it out.
🍍 Ethyl Butyrate (ethanol + butyric acid) – Pineapple and tropical fruit. Small but potent. Can add zippy intensity to fruity styles.
🍏 Ethyl Hexanoate (ethanol + hexanoic acid) – Sharp green apple with a waxy edge. Shows up more in long ferments with good yeast health and oxygen control.
🌸 Phenethyl Acetate (phenethyl alcohol + acetic acid) – Rosewater, floral perfume. Slower, cooler fermentations tend to favour its formation — elegant and aromatic.
🍇 Ethyl Caprylate (ethanol + caprylic acid) – Grape skin, juicy fruit, wine-like depth. Often found in richer distillates and higher ester ferments.
These esters survive distillation — and evolve in the cask — but the fruit is already built into the spirit.
📎 Infographic attached
If you’d like a clean, high-resolution version for training or education, feel free to get in touch.
This just scratches the surface — things like pH, oxygen, fermentation time, and yeast nutrients all influence how esters form and behave.
If you’re working on flavour training or need bespoke visuals, I’m always happy to help.
💬 Got a favourite fruit-forward dram? 🍍🍇🍌
Is it yeast you’re tasting — or oak?