Bronner

Summary

Bronner is a foundational white PIWI variety developed at the Freiburg Research Institute in Germany, critically important both as a wine grape and as a parent variety for subsequent PIWI breeding. Released in 1975, Bronner has been instrumental in creating many of today’s leading PIWI varieties, passing on its exceptional disease resistance genetics. As a wine grape, Bronner produces neutral to lightly aromatic white wines with good acidity, suitable for fresh, crisp styles. With approximately 300 hectares globally, Bronner continues to play a dual role in sustainable viticulture—as a reliable producer and as a genetic foundation for future varieties.

Identity

VIVC: Entry #5174
Berry Color: BLANC
Type: PIWI (Interspecific hybrid)

Breeding Number: FR 250-75

Creator: Norbert Becker, Staatliches Weinbauinstitut Freiburg, Germany
Year: 1975

Name Origin: Named after Johann Philipp Bronner (1792-1864), German wine pioneer and author who documented grape varieties and promoted quality viticulture.

Genetic Origin

Parentage: Merzling × Gm 6494

Breaking down the parentage:

Merzling: First-generation PIWI (Seyval blanc × a Riesling cross); provides disease resistance and wine quality
Gm 6494: Geilweilerhof breeding line with multiple resistance genes

Breeding Achievement: Created a highly disease-resistant variety that could pass on those traits to offspring

Importance as Breeding Parent

Bronner’s genetic legacy is enormous—parent to many leading PIWI varieties:

Offspring	Cross	Type	Character
Souvignier Gris	Cabernet Sauvignon × Bronner	White (grey skin)	Premium, aromatic
Cabernet Blanc	Cabernet Sauvignon × Bronner	White	Aromatic
Cabernet Cortis	Cabernet Sauvignon × Bronner	Red	Cabernet-style
Divico	Gamaret × Bronner	Red	Premium Swiss
Muscaris	Solaris × Bronner	White	Aromatic
Prior	Complex × Bronner	Red	Early ripening

This makes Bronner one of the most important PIWI breeding parents in history.

Disease Resistance Profile

Disease	Resistance Level	Notes
Downy Mildew	HIGH	Strong resistance
Powdery Mildew	HIGH	Strong resistance
Botrytis	MEDIUM	Some susceptibility
Black Rot	HIGH	Good resistance

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

Genetic Value: Passes resistance traits effectively to offspring

Distribution

Total Global Plantings: ~300 hectares

Country	Hectares	Notes
Germany	~150	Origin; established
Switzerland	~80	Significant adoption
Austria	~40	Growing
Italy (South Tyrol)	~20	Emerging
Other	~10	Various

Viticulture

Growth Characteristics

Vigor: Medium to high
Growth Habit: Semi-erect
Budbreak: Medium
Flowering: Mid-season
Véraison: Medium
Harvest: Medium-late

Climate Requirements

Ideal Climate: Cool to moderate continental
Heat Summation: 1,100-1,500 GDD (base 10°C)
Frost: Good tolerance
Adaptability: Central European conditions

Soil Preferences

Adaptable: Various wine soils
Ideal: Well-drained with moderate fertility
Effect: Terroir influences wine character

Viticultural Management

Training: Guyot or cordon
Pruning: Standard practices
Yield Control: 60-80 hl/ha
Spray Program: Significantly reduced

Enology

Must Parameters at Harvest

Parameter	Typical Range	Notes
Brix	20-23°	Good accumulation
pH	3.1-3.4	Moderate
Titratable Acidity	6.0-8.0 g/L	Good
YAN	180-260 mg/L	Generally adequate

Wine Character

Neutral: Not strongly aromatic
Clean: No hybrid character
Versatile: Adaptable to styles

Fermentation

Yeast Selection: Neutral to aromatic yeasts
Temperature: 14-18°C
Duration: 14-21 days
Goal: Clean fermentation

Wine Styles

Style	Method	Character
Fresh	Stainless steel, quick bottling	Crisp, neutral
Aromatic	Skin contact, aromatic yeasts	Enhanced expression
Blend	With aromatic varieties	Adds structure
Sparkling	Traditional method	Good base wine

Malolactic Fermentation

Typical: Blocked for freshness
High Acid Years: Optional partial MLF
Result: Crisp, clean profile

Aging Potential

Fresh Style: 1-3 years
Character: Best enjoyed young

Sensory Profile

Visual

Intensity: Pale to medium
Hue: Greenish-yellow
Character: Bright, clear

Aromatic Profile

Category	Descriptors
Fruit	Green apple, citrus, pear
Herbal	Herbaceous notes
Mineral	Flinty hints
Other	Clean, neutral base

Palate

Body: Light to medium
Acidity: Medium to medium-high
Alcohol: Moderate (11-13%)
Finish: Clean, crisp

Style Description

Bronner produces wines that are:

Clean and neutral
Crisp and refreshing
Versatile base for blending
Free of hybrid character

Winemaker Considerations

Challenges

Neutral Character: Less aromatic complexity
Market Position: Competes with other white PIWI
Recognition: Often overshadowed by offspring
Botrytis: Moderate susceptibility
Yields: Can overcrop

Opportunities

Reliability: Consistent performer
Blend Base: Neutral character suits blending
Sustainability: Excellent disease resistance
Sparkling Base: Good acidity for méthode
Organic Production: Ideal candidate

Winemaking Tips

Consider skin contact for added character
Aromatic yeasts can enhance profile
Blend with aromatic varieties
Good sparkling wine base
Market sustainability credentials

Historical Significance

Bronner’s contributions to viticulture:

Breeding Foundation: Parent to numerous PIWI varieties
Research Validation: Proved PIWI concept viable
Sustainable Pioneer: Enabled organic production
Genetic Resource: Continues to contribute to breeding

Characteristic	Bronner	Merzling (parent)	Souvignier Gris (offspring)
Character	Neutral	Neutral	Aromatic, rich
Body	Light	Light	Full
Resistance	High	Medium-High	High
Role	Wine + breeding	Pioneer breeding	Premium wine

Sources

VIVC Database - Vitis International Variety Catalogue
Staatliches Weinbauinstitut Freiburg
PIWI International Association
German Wine Institute
Becker, N. (2000). PIWI breeding at Freiburg. Vitis 39(4). Vitis Journal

Last Updated: January 13, 2026