Volatile thiols

Varietal aromas of Sauvignon blanc

The varietal aromas of Sauvignon blanc are the most well-known of the non-Muscat grape varieties. The main descriptors used to describe these aromas are known to be derived from specific molecules:

  • 4MMP (4-mercaptopentan-2-one) was the first identified.  It has a strong odour of box tree and broom.
  • 3MHA (3-mercaptohexyl acetate) has box tree and passionfruit nuances.
  • 3MH (3-mercaptohexan-1-ol) is responsible for grapefruit and passionfruit odours (see also cysteinytaled precursor page).

Other grapes varieties

Wines made from premium Alsatian grape varieties such as Gewürtzaminer, Muscat, Riesling, Pinot gris, as well as wines from Colombard, Chenin blanc, Sauvignon blanc and Sémillon infected by noble rot, can present a sauvignon-like character. In all those wines, the volatile thiols can reach and exceed their perception thresholds. Also, in some wines, levels can be higher than those found in Sauvignon blanc.

Rosé wines

Extensive analyses carried out in our laboratory confirmed the presence of 3MH and its acetate (at concentrations sometimes well above the perception threshold) in many rosé wines made from the most common red grape varieties: Merlot, Cabernet Sauvignon, Cabernet Franc, Grenache, Syrah, Cinsault, Mourvèdre, Pinot Noir, and Malbec, irrespective of their geographical origin.

Red wines

Young red wine of the these grape varieties may also contain high 3MH and 3MHA levels.

Why quantify volatile thiols in wines?

Vineyard management

4MMP and 3MH are derived from odourless cysteinylated precursors present in grapes (see also the page  “cysteinytaled precursor”). The volatile thiol content of wines thus depends on the precursor content of grapes, which is affected by climate and soil conditions (in particular water and nitrogen uptake), as well as harvest date. Volatile thiols can be analysed in the corresponding wines to compare different techniques of vineyard management.

Winemaking management

Skin contact, the duration and temperature of skin contact, as well as choice of yeast strain, yeast nutrition, fermentation temperature, maturation method etc. all have a great impact on the final level of 4MMP, 3MH and 3MHA in wine. Volatile thiols can thus be analysed to compare and to validate different winemaking techniques.

Blending decision

When combined with wine tasting, volatile thiol analysis is useful to monitor Sauvignon-like aroma in the final wine blend.

Compound

4MMP, 3MH, 3MHA

Method

GC/MS

Volume

125 mL*

Analysis duration

5 days

*Wine must be properly sulphited.

Our quality guarantee

  • Method validated according to OIV Oeno 10/2005 resolution and NF V03-110 standard validation
Sarco

Laboratoire Sarco®   -  25, rue Aristide Bergès 33270 FLOIRAC - +33 5 57 77 96 27 - This email address is being protected from spambots. You need JavaScript enabled to view it.