🍷 Secondary aromas
Also known as: secondary aromas, fermentation aromas, secondary aroma, yeast aromas, winemaking aromas
Secondary aromas are wine smells made during fermentation: esters, higher alcohols and the buttery note of diacetyl from lactic acid bacteria.
Secondary aromas (fermentation aromas, yeast aromas) are wine smells that are born not in the berry but during fermentation. Yeasts make them: they give the winey base of the smell and sometimes fruity notes. The group includes higher alcohols, esters, carbonyl and sulfur compounds.
A 2022 paper by Romano and colleagues is specific about them. Isoamyl acetate smells of banana and pear, ethyl hexanoate of green apple and 2-phenylethyl alcohol of rose. Ethyl octanoate brings a soapy note. Acetaldehyde is pleasantly fruity in small doses, but in excess it smells grassy.
A special case is diacetyl. It is the buttery note, made by lactic acid bacteria, and Oenococcus oeni breaks it down during malolactic fermentation. The same fermentation lowers acidity. How much diacetyl is left depends on the bacterial strain, pH, temperature, citric acid, sulfur dioxide, aeration, yeast lees and phenolics.
Compare the other groups. Primary aromas come from the berry itself, while Bouquet (wine) is about ageing. Many compounds, among them thiols, terpenes and esters, form or are released in fermentation from odourless precursors. The overall scheme is in Wine aroma, and the butter note is on the page Diacetyl.
Facts
| Main use | Formed during fermentation by yeasts and lactic acid bacteria 13 |
|---|---|
| Taste | Isoamyl acetate: banana and pear; ethyl hexanoate: green apple; diacetyl: butter 13 |
| Acidity | Malolactic fermentation reduces acidity 3 |
How it connects to Wine
🍷 Secondary aromas → kind of → 🍷 Wine aroma → kind of → 🍷 Wine taste and composition → kind of → 🍷 Wine
Links
- Part of
- 🍷 Wine aroma
Frequently asked questions
Which compounds count as secondary aromas?
Higher alcohols, esters, carbonyl and sulfur compounds, made mostly by yeast [1].
Why does some wine smell of butter?
Diacetyl, produced by lactic acid bacteria. Oenococcus oeni handles it during malolactic fermentation [3].
Which ester smells of banana?
Isoamyl acetate, which gives banana and pear. Ethyl hexanoate gives green apple [1].
Does malolactic fermentation change more than smell?
Yes. It also reduces acidity [3].
Is it true that all fruity smells in wine come from the grape?
No. Some fruity notes, such as esters, arise during fermentation [1][2].
Similar
🍷 Primary aromas · 🍷 Bouquet (wine) · 🍷 Wine aroma wheel · 🍷 Minerality
What it includes
Sources
- P. Romano et al. Role of Yeasts on the Sensory Component of Wines. Foods 11(13), 2022
- C. van Leeuwen et al. Recent advancements in understanding the terroir effect on aromas in grapes and wines. OENO One 54(4), 2020
- E. J. Bartowsky, P. A. Henschke. The 'buttery' attribute of wine: diacetyl, desirability, spoilage and beyond. International Journal of Food Microbiology 96(3), 2004