Solaris

Summary

Solaris is one of the most widely planted white PIWI (Pilzwiderstandsfähig/fungus-resistant) varieties globally, particularly important in cool and marginal climates where its exceptionally early ripening and strong disease resistance enable quality wine production without chemical intervention. Developed at Freiburg, Germany in 1975, Solaris produces aromatic wines with Muscat-like character, tropical fruit notes, and good acidity. The variety has been instrumental in establishing viticulture in Scandinavia, where traditional varieties cannot ripen, and is increasingly important in sustainable and organic wine production across Northern Europe.

Identity

VIVC: Entry #20340
Berry Color: BLANC
Type: PIWI (Interspecific hybrid)

Breeding Number: FR 240-75 (Freiburg)

Creator: Norbert Becker, Staatliches Weinbauinstitut Freiburg, Germany (1975)

Registration: Registered in Germany 2001; EU-wide authorization 2004

Genetic Origin

Parentage: Merzling × (Zarya Severa × Muscat Ottonel)

Breaking down the parentage:

• Merzling: PIWI variety (Seyval Blanc × multiple Vitis species)
• Zarya Severa: Russian cold-hardy variety
• Muscat Ottonel: Aromatic Vitis vinifera (contributes terpenes)

Breeding Goals:

1. Early ripening for cool climates
2. Strong fungal disease resistance
3. Good wine quality
4. High sugar accumulation

Result: Successfully achieved all goals; one of the most successful PIWI varieties.

Disease Resistance Profile

Disease	Resistance Level	Notes
Downy Mildew	VERY HIGH	Near immune
Powdery Mildew	HIGH	Rarely requires treatment
Botrytis	MEDIUM	Some susceptibility; early harvest helps
Black Rot	HIGH	Good resistance
Phomopsis	HIGH	Good resistance

Spray Reduction: 70-90% reduction vs. traditional varieties

Organic/Biodynamic: Ideal variety; minimal intervention required

Distribution

Total Global Plantings: ~1,500 hectares (and growing)

Country/Region	Hectares	Status
Germany	~300	Established
Poland	~200	Major variety
Sweden	~150	Primary variety
Denmark	~100	Primary variety
England	~100	Significant
Norway	~50	Important
Belgium	~80	Growing
Netherlands	~70	Growing
Other	~450	Various

Growth Trend: Rapidly expanding, especially in:

• Scandinavia (primary variety)
• Benelux countries
• Northern Germany
• Cool-climate emerging regions

Viticulture

Growth Characteristics

• Vigor: Medium to high
• Growth Habit: Semi-erect
• Budbreak: Medium-early
• Flowering: Early
• Véraison: Very early
• Harvest: VERY EARLY (August-September in Germany)

The Early Ripening Advantage

Solaris’s very early ripening is critical:

• Germany: Harvested 2-4 weeks before Riesling
• Scandinavia: Enables ripening where traditional varieties fail
• Sugar: Can reach 100+ Oechsle (24+ Brix)
• Climate: Extends wine production northward

Climate Requirements

• Ideal Climate: Cool to marginal
• Heat Summation: 900-1,400 GDD (very low requirement)
• Northern Limit: 60°N latitude (Southern Sweden/Norway)
• Frost: Good tolerance

Soil Preferences

• Adaptable: Performs on various soils
• Ideal: Well-drained, moderate fertility
• Avoid: Very fertile soils (excessive vigor)

Viticultural Management

• Training: VSP standard
• Pruning: Moderate bud load
• Yield Control: Moderate yields (60-80 hl/ha)
• Spray Program: Minimal—the key advantage
• Harvest: Monitor sugar carefully (can over-ripen)

Rootstock Compatibility

• Preferred: SO4, 5BB
• Compatible: Various
• Note: Less rootstock research than for traditional varieties

Enology

Must Parameters at Harvest

Parameter	Typical Range	Notes
Brix	22-26°	Can be very high
pH	3.1-3.4	Good
Titratable Acidity	6.0-8.5 g/L	Good retention
YAN	180-280 mg/L	Generally adequate

The High Sugar Challenge

Solaris can accumulate excessive sugar:

• Monitoring: Critical—sugar rises rapidly
• Harvest Decision: Don’t wait too long
• Alcohol Management: May need early harvest for balance
• Style Choice: Match ripeness to intended style

Aroma Compounds

• Terpenes: HIGH (from Muscat Ottonel heritage)
  • Linalool, geraniol, nerol
• Thiols: Moderate (tropical notes)
• C13-Norisoprenoids: Present
• Character: Aromatic, Muscat-like

Fermentation

• Yeast Selection: Aromatic yeasts enhance terpenes
• Temperature: 14-18°C (preserve aromatics)
• Duration: 14-21 days
• Vessel: Stainless steel (standard)

Malolactic Fermentation

• Standard Practice: Usually blocked
• Reason: Preserve freshness and acidity
• Alternative: Partial MLF for fuller styles

Oak Treatment

• Standard: None
• Philosophy: Preserve aromatic character
• Alternative: Brief neutral oak for texture

Wine Styles

Style	Method	Character
Fresh/Aromatic	Early harvest, no MLF	Floral, tropical, crisp
Richer	Later harvest	Fuller, stone fruit
Off-Dry	Arrested fermentation	Residual sugar, aromatic
Sparkling	Traditional method	Aromatic base wine
Late Harvest	Extended hang time	Sweet, concentrated

Sensory Profile

Visual

• Intensity: Pale to medium
• Hue: Straw with green-gold hints
• Clarity: Brilliant

Aromatic Profile

Category	Descriptors
Floral	Muscat, elderflower, rose
Tropical	Passionfruit, mango, pineapple
Citrus	Grapefruit, lemon, lime
Stone Fruit	Peach, apricot
Herbal	Fresh herbs
Other	Honeyed notes when ripe

Palate

• Body: Light to medium
• Acidity: Medium to medium-high
• Texture: Fresh, clean
• Finish: Aromatic, moderate length
• Alcohol: Variable (11-14%+ depending on harvest)

Winemaker Considerations

Challenges

1. Sugar Monitoring: Can over-ripen quickly
2. Vigor Management: High vigor on fertile soils
3. Style Decision: Wide range possible
4. Market Position: PIWI varieties still building reputation
5. Botrytis Risk: Some susceptibility remains

Opportunities

1. Sustainability: Minimal spray requirement
2. Cool Climate Pioneer: Enables new wine regions
3. Organic/Biodynamic: Ideal for low-intervention
4. Climate Change: Valuable as conditions warm
5. Cost Savings: Reduced vineyard treatments

Winemaking Tips

• Harvest based on flavor and acidity, not just sugar
• Protect aromatics during processing
• Cool fermentation essential
• Consider slight residual sugar to balance high alcohol
• Early bottling preserves freshness

Permitted Appellations

Fully Authorized

• Germany: Qualitätswein in all 13 Anbaugebiete
• Switzerland: Various AOC wines
• England: English Wine PDO
• Sweden: All wine regions
• Denmark: Danish wine regions
• Norway: Norwegian wine regions
• Poland: Quality wine designation
• Belgium: Belgian wine regions
• Netherlands: Dutch wine regions

Scandinavia: The New Frontier

Solaris has been instrumental in creating Scandinavian viticulture:

Sweden

• Primary white variety
• Regions: Skåne, Gotland
• Growing degree days: Limited but sufficient for Solaris
• Production: ~150 hectares

Denmark

• Significant plantings
• Quality improving rapidly
• Both still and sparkling production

Norway

• Northernmost commercial vineyards
• Relies heavily on Solaris
• Challenging but successful

Comparison with Other PIWI Whites

Characteristic	Solaris	Johanniter	Muscaris
Ripening	Very Early	Early	Medium
Downy Resistance	Very High	High	High
Aromatics	High (Muscat)	Medium	Very High
Sugar	Very High	Medium	Medium
Best Climate	Cool/Marginal	Cool	Moderate

Sustainability Impact

Solaris exemplifies PIWI benefits:

• Spray Reduction: 70-90% fewer fungicide applications
• Carbon Footprint: Reduced tractor passes
• Biodiversity: Less chemical impact on vineyard ecosystem
• Economics: Lower production costs
• Certification: Easier organic/biodynamic compliance

Sources

• Robinson, J., Harding, J., & Vouillamoz, J. (2012). Wine Grapes. Ecco/HarperCollins. Publisher Link
• VIVC Database - Vitis International Variety Catalogue
• Staatliches Weinbauinstitut Freiburg (breeding institution)
• PIWI International Association
• Nordic Wine Producers Association
• Becker, N. (2000). Breeding of new fungus-resistant grape varieties. Vitis 39(4). Vitis Journal

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Last Updated: January 13, 2026