Low SO2, low H2S and low acetaldehyde wine yeasts
Key takeaways
What are the benefits for winemakers?
Technical benefits
Lower production of:
- SO₂ -> lower final SO2 content in wines
- H₂S -> decrease of sulfur related off flavors
- Acetaldehyde -> decrease of SO2 binding effect: helps to reduce SO2 addition through a better efficiency of those additions.
- Improved fermentation reliability
- Better compatibility with low‑SO₂ strategies
Sensory benefits
- Clearer fruit expression
- Reduced masking by sulphur compounds
- Fresher, cleaner aromatic profiles
Why do wine yeasts influence SO₂, H₂S and acetaldehyde levels?
Wine yeasts are not neutral fermenters.
- SO₂, H₂S and acetaldehyde are yeast‑dependent compounds and large variability exists between strains
- These compounds directly affect:
- SO₂ management
- Aromatic expression
- Risk of reductive off‑odours
- Consumer considerations for lower SO2 wines
Choosing the right yeast is therefore a strategic decision, not just a fermentation choice.
What is the QTL yeast selection method?
QTL (Quantitative Trait Loci) mapping links a phenotype to specific genetic regions.
In practice, it means:
- Identifying genes responsible for:
- Low SO₂ production
- Low H₂S release
- Reduced acetaldehyde production
- Tracking these genes using molecular markers
- Transferring them into high‑performance wine yeasts through repeated backcrossing
Is QTL yeast selection a GMO technology?
No.
QTL yeasts are:
- Non‑GMO
- Non‑NGT
- Based on natural yeast breeding
- Occurring within the species Saccharomyces cerevisiae
The process mimics natural genetics, but with scientific precision.
How does QTL selection reduce sulphur compounds?
Mechanism (simplified)
- QTL mapping identified key genes (e.g. MET2, SKP2) involved in sulphur metabolism
- Combining the right alleles:
- Limits SO₂ overproduction
- Avoids sulphur overflow as H₂S
- Indirectly reduces acetaldehyde formation
Which yeasts are selected using the QTL approach?
| Yeast | Wine style & key benefits |
| LALVIN® ICV OKAY™ | Robust fermentations, very low SO₂ / H₂S / acetaldehyde |
| LALVIN® SENSY™ | White wines, varietal expression, reduced sulphur compounds |
| LALVIN® ICV Opale 2.0™ | Aromatic whites & rosés, exotic and fresh profiles |
(All selected using QTL‑assisted backcrossing!)
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Published May 13, 2026 | Updated May 19, 2026
Wine Yeast