The composition of standard butter
When you buy a standard stick of butter from the grocery store, you are not purchasing 100% pure milkfat. By legal definition in the United States, butter must contain at least 80% milkfat, with the remaining percentage composed primarily of water and a small amount of milk solids-not-fat (MSNF). Salt may also be added, which slightly reduces the fat percentage. This is because butter is an emulsion—specifically, a water-in-oil emulsion. During the churning process, the fatty part of the cream is separated from the liquid buttermilk. However, a small amount of water and protein solids remains trapped within the final product.
The typical composition of a standard stick of butter includes:
- Milkfat: Approximately 80–82%
- Water: 14–18%
- Milk Solids (lactose, casein, whey, minerals): 1–2%
- Salt (if salted): Up to 2%
The path to 100% butterfat
While a regular stick of butter is not 100% fat, it is possible to create a dairy product that is nearly pure milkfat. This product is known as anhydrous milkfat, butter oil, or ghee. The process involves clarifying butter, which means removing the water and milk solids. Ghee, in particular, is a shelf-stable product composed of at least 99.5% milkfat. The journey from cream to pure butterfat involves several stages of separation and heat treatment, with the end product being a highly concentrated and flavorful fat source.
Clarified butter vs. ghee
There are two primary methods for achieving a higher milkfat product. Both rely on heat to separate the butter's components, but they differ slightly in process and result:
- Clarified Butter: The most straightforward method involves melting butter slowly over low heat. The butter will separate into three distinct layers: a foamy top layer (milk solids), a clear, golden middle layer (butterfat), and a milky bottom layer (water and milk solids). The butterfat can then be carefully skimmed and strained, leaving behind a clarified butter with a higher smoke point. This version is not always completely anhydrous and is typically stored in the refrigerator.
- Ghee (Anhydrous Milkfat): Ghee is a specific type of clarified butter that is cooked longer and often at a higher temperature. This process causes the milk solids to brown and caramelize, adding a nutty, toasted flavor before they are strained out completely. The longer heating ensures that all the water evaporates, leaving a product that is typically over 99.5% pure milkfat and shelf-stable for long periods without refrigeration.
Understanding high-fat butters
For those seeking a product closer to pure butterfat without full clarification, there are "European-style" butters available. These butters typically boast a higher milkfat percentage, often 82% to 85%, compared to the American standard of 80%. This higher fat content results in a richer flavor, creamier texture, and faster melting time, making them a popular choice for baking and professional pastry applications. Brands like Kerrygold and Plugra are known for this higher fat content.
Comparison Table: Butter vs. Clarified Butter vs. Ghee
| Feature | Standard Butter | Clarified Butter | Ghee |
|---|---|---|---|
| Milkfat % | ~80-85% | ~99%+ | ~99.5%+ |
| Composition | Milkfat, water, milk solids | Mostly milkfat | Pure butterfat |
| Water | Present (14-18%) | Mostly removed | Fully evaporated |
| Milk Solids | Present (1-2%) | Mostly removed | Fully removed, often browned |
| Flavor Profile | Creamy | Richer, earthy | Nutty, caramelized |
| Smoke Point | ~350°F (177°C) | ~450°F (232°C) | ~485°F (252°C) |
| Shelf-Stability | Requires refrigeration | Needs refrigeration | Shelf-stable (room temp) |
| Lactose Content | Contains lactose | Very low lactose | Lactose-free |
Why purity matters for cooking
The key differences between these products lie in their composition and, consequently, their properties in the kitchen. The water and milk solids in standard butter are what cause it to smoke and burn at lower temperatures. When cooking over high heat, these elements can degrade, producing acrid or bitter notes.
The removal of these volatile components in clarified butter and ghee makes them ideal for sautéing, searing, and deep-frying. This higher smoke point allows for intense heat without burning, preserving the rich, buttery flavor. Additionally, the lack of moisture prevents splattering.
In baking, the choice between standard butter and pure butterfat depends entirely on the desired outcome. Standard butter's water content is critical for creating steam, which contributes to the flaky layers in laminated pastries like croissants. On the other hand, the rich flavor of clarified butter can be beneficial in certain sauces or for finishing dishes. A valuable resource on the topic can be found at the Canadian Dairy Commission's overview of butter.
Can you make nearly 100% butter at home?
Technically, you cannot create churned butter with 100% milkfat at home, as the churning process traps some water and milk solids. However, you can make your own clarified butter or ghee. Here’s a simple process for making ghee at home:
- Melt: Place a block of unsalted butter in a saucepan over low to medium heat.
- Simmer: Allow the butter to simmer gently. As it melts, foam will form on the surface, and the milk solids will sink to the bottom.
- Monitor: Continue to cook until the foam subsides and the milk solids on the bottom turn a golden brown color, releasing a nutty aroma.
- Strain: Carefully pour the clear, liquid butterfat through a fine-mesh sieve lined with cheesecloth or a coffee filter.
- Store: Let the liquid ghee cool before storing it in an airtight container, where it will solidify.
Conclusion
In conclusion, the idea of "100% butter" is a misnomer for the product most people recognize. By definition, standard butter contains around 80% milkfat, with the remaining percentage being water and milk solids. For those seeking a product that is nearly pure milkfat, the solution lies in creating clarified butter or ghee, which involves removing these non-fat components through a heating and straining process. The product you choose depends on your cooking needs, whether it's the creaminess and flakiness from standard butter or the high-heat stability and rich flavor of pure butterfat. Understanding the difference is key to mastering different culinary techniques.
