What is Culture in Cheese? The Secret Ingredient
In cheese, culture refers to the live microorganisms, primarily bacteria but sometimes including yeasts and molds, added to milk to initiate the cheesemaking process. These cultures play a critical role in flavor development, texture formation, and overall cheese characteristics.
The Backbone of Cheesemaking
The term “culture” in the context of cheesemaking refers to the intentional addition of specific microorganisms to milk to kickstart the fermentation process. Without these cultures, the milk wouldn’t transform into the delicious, diverse range of cheeses we know and love. Think of them as tiny chefs, carefully orchestrating a complex biochemical transformation.
Beyond the Basics: Benefits of Cultures
Cultures aren’t just about turning milk into curds. They’re responsible for a host of crucial functions that directly impact the quality and character of the final product:
- Acid Production: Cultures ferment lactose (milk sugar) into lactic acid, lowering the pH. This acidity is essential for curd formation and impacts the cheese’s texture and flavor.
- Flavor Development: Different culture strains produce different enzymes that break down proteins and fats, releasing volatile aromatic compounds. This is where the complex and nuanced flavors of cheese originate.
- Texture Formation: Acid production influences the structure of the curd, affecting the cheese’s firmness, elasticity, and meltability. Some cultures also produce exopolysaccharides, contributing to a creamy texture.
- Inhibition of Undesirable Microorganisms: Cultures can outcompete and suppress the growth of spoilage bacteria and pathogens, ensuring food safety and extending shelf life.
- Aroma Creation: Cultures create the signature aromas of cheese, ranging from buttery and nutty to earthy and pungent.
A Step-by-Step Look at the Culturing Process
The culturing process varies slightly depending on the type of cheese being made, but the general steps are:
- Selecting the Right Culture: Cheesemakers choose specific culture strains based on the desired flavor, texture, and aging characteristics of the cheese. These can be single-strain or mixed-strain cultures.
- Preparing the Culture: Cultures can be in frozen, freeze-dried, or liquid form. Frozen or freeze-dried cultures must be rehydrated or activated according to the manufacturer’s instructions.
- Inoculating the Milk: The activated culture is added to the pasteurized or raw milk at a specific temperature, typically around 90°F (32°C).
- Incubation: The milk is held at a controlled temperature for a specific period, allowing the culture to multiply and begin fermenting lactose.
- Monitoring Acidity: The cheesemaker monitors the milk’s acidity (pH) as the culture works. This is crucial for determining when to proceed to the next stage of cheesemaking.
Classifying Cultures: A Quick Guide
Cultures are broadly classified into mesophilic and thermophilic, based on their optimal growth temperatures.
| Culture Type | Optimal Temperature Range | Common Cheese Types | Characteristics |
|---|---|---|---|
| Mesophilic | 68-86°F (20-30°C) | Cheddar, Gouda, Feta | Typically produces milder flavors, less acid. |
| Thermophilic | 104-122°F (40-50°C) | Mozzarella, Parmesan, Gruyere | Produces higher acidity and stronger flavors. |
Beyond mesophilic and thermophilic, there are also specialized cultures like:
- Surface Cultures: Penicillium molds used to create bloomy rind cheeses like Brie and Camembert.
- Propionibacterium: Used in Swiss cheeses to produce carbon dioxide, creating the characteristic holes or “eyes.”
- Yeast: Contributing to unique flavor profiles in some cheeses, such as washed-rind cheeses.
Common Mistakes and How to Avoid Them
While cheesemaking may sound straightforward, working with cultures requires precision and attention to detail. Here are some common mistakes:
- Using Expired Cultures: Cultures have a limited shelf life. Check the expiration date before using them. Expired cultures will result in slow or incomplete fermentation.
- Improper Storage: Store cultures according to the manufacturer’s instructions, typically in a cool, dry place or in the freezer.
- Incorrect Temperature: Using milk that is too hot or too cold can inhibit culture growth. Ensure the milk is at the optimal temperature for the selected culture.
- Contamination: Maintaining a clean work environment is essential to prevent contamination by unwanted microorganisms. Always sanitize equipment and utensils before use.
- Over-Acidification: Allowing the culture to ferment for too long can result in an overly acidic cheese. Monitor pH levels carefully and proceed to the next stage of cheesemaking when the target acidity is reached.
Frequently Asked Questions (FAQs)
What are starter cultures?
Starter cultures are specially prepared cultures of microorganisms used to initiate the fermentation process in cheesemaking. They typically contain specific strains of bacteria carefully selected for their ability to produce lactic acid, develop flavor, and contribute to the desired texture of the cheese.
Are cultures in cheese the same as probiotics?
While some cultures used in cheesemaking may have probiotic benefits, not all cultures are considered probiotics. Probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Some cheese cultures meet this criterion, but others are primarily selected for their cheesemaking properties rather than their impact on human health.
Can I use yogurt culture to make cheese?
Yes, you can use yogurt culture to make some types of cheese, particularly fresh cheeses like cream cheese or farmer’s cheese. However, yogurt cultures may not produce the same flavor profiles or textures as cultures specifically designed for cheesemaking.
What is the difference between single-strain and mixed-strain cultures?
Single-strain cultures contain only one type of microorganism, while mixed-strain cultures contain a combination of different microorganisms. Single-strain cultures offer more predictable results, while mixed-strain cultures can produce more complex flavors.
What happens if I don’t add culture to the milk?
If you don’t add culture to the milk, it will not properly ferment, and you won’t get cheese. The cultures are essential for producing the lactic acid that lowers the pH and causes the milk proteins to coagulate into curds. Without culture, the milk may spoil instead of turning into cheese.
How do I know if my cheese culture is working?
Signs that your cheese culture is working include a drop in the milk’s pH, thickening of the milk, and a characteristic tangy aroma. You can also use a pH meter or test strips to monitor the acidity of the milk.
Where can I buy cheese cultures?
Cheese cultures can be purchased from cheesemaking supply stores, online retailers specializing in cheesemaking equipment and ingredients, and some health food stores.
Can I reuse cheese culture?
Generally, it is not recommended to reuse commercial cheese cultures. The culture may become contaminated or weakened over time, leading to inconsistent results. However, some cheesemakers use back-slopping techniques, using whey from a previous batch to inoculate a new batch, but this requires experience and careful monitoring.
What is a mother culture?
A mother culture is a larger quantity of culture prepared from a small starter culture. It is used to inoculate larger batches of milk for cheesemaking. Cheesemakers often prepare mother cultures to ensure they have a sufficient quantity of active culture for their cheesemaking needs.
Does raw milk cheese need culture?
Even when using raw milk, adding specific cheese cultures is still important. While raw milk naturally contains microorganisms, these are not always the ideal types or in the sufficient quantities for cheesemaking. Adding specific cultures ensures predictable fermentation and flavor development.
How long does it take for culture to work?
The time it takes for culture to work depends on the type of culture, the temperature of the milk, and the desired acidity level. Typically, it takes between 30 minutes to several hours for the culture to significantly lower the pH of the milk.
Can too much culture ruin the cheese?
Yes, adding too much culture can result in over-acidification, leading to a cheese with a sour or bitter flavor and a dry, crumbly texture. It’s important to follow the manufacturer’s instructions and use the recommended amount of culture for the volume of milk being used.