When you bite into a Camembert or Crottin de Chavignol, have you ever wondered about its wrinkly velvety rind? Behind that delicate exterior lies Geotrichum candidum, a yeast-like fungus that plays a vital role in crafting some of the world’s finest cheeses. From its ability to shape a cheese’s texture to its impact on flavour, G. candidum is a cheesemaker’s secret weapon.
What type of organism is Geotrichum candidum?
Geotrichum candidum is a yeast-like fungus that straddles the boundary between yeast and mould. Unlike typical yeast, which is single-celled, G. candidum forms a mycelial structure made up of branching filaments. It is classified as a “filamentous yeast” due to its ability to grow in thread-like structures similar to moulds.
This fungus belongs to the family Dipodascaceae and thrives in environments rich in proteins and fats, making it ideal for cheesemaking. Its dual nature allows it to break down complex molecules in cheese, contributing to the formation of both the rind and the soft, creamy interior of surface-ripened cheeses.
Its unique characteristics make it indispensable in crafting cheeses like Camembert and a large number of French goat’s milk cheeses.
Here’s a table comparing mould and yeast:
| Feature | Mould | Yeast |
|---|---|---|
| Definition | A type of fungus that grows as multicellular filaments (hyphae). | A type of fungus that grows as single-celled organisms. |
| Form | Multicellular and filamentous. | Unicellular, though some form chains (pseudohyphae). |
| Reproduction | Reproduces by producing spores. | Reproduces through budding or fission. |
| Appearance | Fuzzy or powdery colonies on surfaces. | Smooth, creamy colonies on growth media. |
| Role in nature | Decomposes organic matter and disperses spores. | Ferments sugars, aids in decomposition and can act as a pathogen. |
| Use in cheese | Ripens rinds, forms blue veins (e.g., Penicillium roqueforti). | Enhances flavour and aroma, aids rind development (e.g., Geotrichum candidum). |
How does Geotrichum candidum get into cheese?
Cheesemakers introduce Geotrichum candidum to cheese in several ways, depending on their desired results.
- Direct inoculation: Spores are added directly to milk or curd during cheesemaking. This ensures G. candidum is present from the beginning of the process.
- Surface application: After moulding, cheesemakers spray or brush a solution containing spores onto the cheese surface. This guarantees even coverage for consistent rind formation.
- Co-inoculation with other microbes: G. candidum is often paired with Penicillium camemberti or Brevibacterium aurantiacum. These organisms work together to ripen cheese and add complexity.
- Natural colonisation: In some traditional cheeses, G. candidum naturally settles on the cheese from the environment. While unpredictable, this method adds a unique, artisanal touch.
- Cross-contamination: Rind cultures can transfer via tools, ripening racks or shared cheesemaking environments. Actually, many farmhouse cheeses rely on this “house flora” for character.
Influence on organoleptic properties of cheese
This yeast doesn’t just create the rind of surface-ripened cheeses; it also generates unique aromas and flavours. Let’s take a closer look at this impact.
Rind development
Once introduced, Geotrichum candidum begins to grow on the cheese’s surface. Once activated by the moisture and nutrients in the cheese, it forms hyphae, which are branching, thread-like structures. These hyphae spread across the surface, creating an intricate mycelial network.
This texture serves more than just aesthetics—it helps regulate the cheese’s moisture. G. candidum reduces excessive surface moisture, preventing spoilage while maintaining the ideal conditions for ripening.
Aromas
As G. candidum metabolises the cheese’s surface, it releases enzymes that break down proteins and fats. This produces characteristic aromas, such as:
- Mild mushroom notes.
- Hints of earthiness or nuts.
- A subtle tang that balances the cheese’s creaminess.
These aromas make surface-ripened cheeses like Wabash Cannonball and Valençay so irresistible.
Flavour development
The fungus also contributes to flavour. Its enzymes soften the cheese and create a creamy, melt-in-your-mouth texture. Over time, G. candidum mellows the cheese’s acidity, replacing spiciness with richness. This complex interplay of flavours makes every bite a sensory delight.
Perfect conditions for Geotrichum candidum
To thrive, Geotrichum candidum needs the right environment:
- Moisture: Cheese surfaces must stay moist to support fungal growth.
- Temperature: It prefers ripening temperatures between 10–15°C.
- Salt: Moderate salting ensures balance, preventing overgrowth.
- Humidity: High humidity (85–95%) is essential for a healthy rind.
Cheesemakers carefully control these factors to achieve consistent results.
Is it safe to eat?
Yes, Geotrichum candidum is safe to eat. This yeast-like fungus is considered non-pathogenic and is widely used in the food industry, particularly in cheesemaking, due to its ability to enhance flavour and texture.
However, people with compromised immune systems or severe allergies should exercise caution with any surface-ripened cheese, as its live cultures could pose a risk in rare cases. For most people, Geotrichum candidum is entirely safe and a delicious component of artisanal cheeses.
3 fun facts about Geotrichum candidum
- It’s a multi-tasking mould: While best known for its role in cheesemaking, Geotrichum candidum is also used in other industries. It can break down organic matter, making it valuable in environmental applications like composting and bioremediation.
- It can eat CDs: G. candidum has an incredible ability to degrade polycarbonate, the material used to make CDs and DVDs. This makes it a fascinating candidate for reducing plastic waste, showcasing its potential beyond the cheeseboard.
- It can ‘bloom’ differently: Depending on temperature and humidity, G. candidum forms different types of rinds. It can range from fine wrinkles to thicker, fuzzy layers.
This versatile microorganism proves that science and deliciousness can go hand in hand!
Can you buy Geotrichum candidum to use at home?
Yes, you can buy Geotrichum candidum for home cheesemaking. It is readily available through cheesemaking supply companies and online retailers.
These are typically sold as freeze-dried spores in small sachets or as part of mixed starter cultures, designed for use in a variety of surface-ripened cheeses.
Where to buy Geotrichum candidum
- Cheesemaking Supply Stores: Many specialty stores stock G. candidum for home cheesemakers. They often offer guidance on using it for specific cheese styles.
- Online Retailers: Websites like Cheesemaking.com, The Cheese Maker, and other niche stores stock G. candidum. You can find options tailored for beginners or advanced cheesemakers.
- Mixed Cultures: Some starter culture blends include G. candidum with other moulds like Penicillium camemberti. These blends are ideal for making cheeses like Camembert.
Using Geotrichum candidum at home
- Direct Inoculation
- Add the spores to milk or curd during the cheesemaking process.
- Follow the recommended dosage on the packet for best results.
- Surface Application
- Dilute the spores in sterilised water or saline solution.
- Spray or brush this mixture onto the cheese surface after moulding.
- Storage
- Store unused G. candidum in the freezer to maintain its potency.
- Use within the shelf life indicated on the packaging.
Tips for success
- Maintain proper temperature (10–15°C) and humidity (85–95%) during ripening.
- Ensure clean tools and surfaces to prevent contamination.
- Monitor the cheese closely to avoid overgrowth or ammonia smells.
With Geotrichum candidum, home cheesemaking becomes even more rewarding. Whether you’re crafting Camembert or a farmhouse-style cheese, it’s a must-have for experimenting with flavour and texture.
Homemade Camembert cheese recipe using Geotrichum candidum
Here’s a beginner-friendly recipe for making Camembert cheese at home. This soft, surface-ripened cheese relies on Geotrichum candidum for its distinctive wrinkly rind and creamy texture.
Ingredients
- 7.6 litres (2 gallons) of pasteurised whole milk (not ultra-pasteurised)
- 1/4 tsp mesophilic starter culture
- 1/16 tsp Penicillium camemberti
- 1/32 tsp Geotrichum candidum
- 1/4 tsp calcium chloride (diluted in 1/4 cup cool, non-chlorinated water, optional for pasteurised milk)
- 1/4 tsp liquid rennet (diluted in 1/4 cup cool, non-chlorinated water)
- Cheese salt
Equipment
- Large stainless steel pot
- Thermometer
- Long knife for cutting curds
- Large spoon or ladle
- Camembert moulds (hoops)
- Cheese mat
- Ripening box
Instructions
- Heat the Milk: Pour the milk into a sterilised pot and heat it slowly to 90°F (32°C). Stir gently to prevent scorching.
- Add Cultures and Moulds: Sprinkle the mesophilic starter, Penicillium camemberti, and Geotrichum candidum over the milk. Let them rehydrate for 2–3 minutes, then stir thoroughly.
- Add Calcium Chloride (Optional): If using pasteurised milk, add diluted calcium chloride. Stir gently to ensure it’s well mixed.
- Coagulate the Milk: Add the diluted rennet and stir gently with an up-and-down motion for 30 seconds. Cover the pot and let the milk set for 90 minutes at 32°C (90°F). The curd should be firm enough to cut when ready.
- Cut the Curd: Use a long knife to cut the curd into 1-inch (2.5 cm) cubes. Let the curds rest for 5 minutes to firm up.
- Transfer Curds to Moulds: Gently ladle the curds into Camembert moulds placed on a draining mat. Fill the moulds evenly and allow the whey to drain naturally.
- Flip the Cheese: After 4–6 hours, flip the cheeses in their moulds. Continue draining for another 6–8 hours.
- Salt the Cheese: Remove the cheeses from the moulds and sprinkle salt evenly on all sides. Let them rest for 24 hours in a cool place.
- Age the Cheese: Place the cheeses on a ripening mat inside a ripening box. Age them at 50–54°F (10–12°C) with 85–90% humidity for 3–4 weeks. Flip the cheeses every 2 days to encourage even rind development.
Notes
- Geotrichum candidum contributes to the wrinkly rind and soft texture, adding earthy and nutty flavours.
- After ageing, store the cheese in the refrigerator to slow ripening.
Enjoy your homemade Camembert, featuring the unique contribution of Geotrichum candidum!
Conclusion
Geotrichum candidum is a quiet yet essential partner in cheesemaking. It transforms bland curds into rich, aromatic masterpieces. Whether creating Brie’s velvety rind or adding complexity to goat’s cheese, this fungus is indispensable.
Next time you savour a slice of Camembert, think about the magic of Geotrichum candidum. Want to learn more about the science behind cheese? Visit Cheese Scientist blog section for insights into your favourite dairy delights.
Cheese lover. Scientist. Created a website and a Youtube channel about cheese science because he could not find answers to his questions online.
