Understanding the Core Concepts: AP vs. EP Weight
At its heart, what is the yield of a food revolves around a simple but crucial distinction between two terms: As Purchased (AP) weight and Edible Portion (EP) weight. The AP weight is the initial weight or volume of a food item as you receive it from a supplier or purchase it from a store. This includes all inedible parts like bones, fat, skins, or peels. The EP weight, on the other hand, is the final usable weight or volume that remains after all preparation and cooking are complete.
For example, if you buy a whole head of cabbage, its AP weight includes the heavy outer leaves and core. After trimming, cleaning, and coring it for a coleslaw recipe, the remaining cabbage is the EP weight. The difference between these two weights is the waste or trim. Understanding this difference is the first step toward accurate recipe costing and efficient inventory management.
The Importance of Calculating Yield Percentage
The yield percentage is a metric that represents the ratio of the edible portion to the as-purchased weight, expressed as a percentage. This calculation provides a powerful insight into the efficiency of your food preparation. The basic formula is:
- Yield Percentage = (EP Weight / AP Weight) x 100
Calculating this percentage allows you to do several things:
- Determine accurate costs: It helps you move from the raw cost of an ingredient to its true, usable cost per unit. This is vital for menu pricing.
- Control inventory and ordering: Knowing the yield helps forecast exactly how much raw product to order for a specific recipe, preventing over-purchasing and waste.
- Improve consistency: Standardized yield calculations ensure that every plate leaving the kitchen has a consistent portion size and quality, leading to better customer satisfaction.
- Reduce waste: By tracking where weight is lost, you can refine preparation techniques and find ways to repurpose trimmings, such as using meat bones for stock.
Factors That Influence Food Yield
The yield of a food is not static; it can be influenced by several factors that occur during the preparation and cooking process. These factors can lead to different types of yield loss.
Types of Yield Loss
- Trimming Loss: This is the weight lost when removing inedible or unwanted parts from an ingredient. Examples include peeling potatoes, deboning chicken, or trimming fat from beef.
- Cooking Loss (Shrinkage): This refers to the loss of weight or volume that occurs during the cooking process, typically due to moisture evaporation or fat rendering. A steak, for instance, will weigh less after grilling than it did before.
- Butchery Loss: In meat and seafood fabrication, this includes all the parts not used for a specific cut, such as bones, skin, and fins.
- Reduction: For sauces and stocks, yield can be intentionally reduced to concentrate flavor through evaporation.
Practical Example: The Case of the Humble Potato
To illustrate these concepts, consider the process of making french fries from whole potatoes. The AP weight is the initial bag of potatoes. The edible portion is the potato flesh left after peeling and cutting. The waste is the peels. Cooking loss then occurs as the fries are fried, with some moisture evaporating. By conducting a yield test, a chef can discover the average yield of their potatoes and use that to calculate the true cost per portion of fries.
Comparison: As Purchased (AP) vs. Edible Portion (EP) Costing
To truly understand the financial impact of food yield, it's helpful to compare two different approaches to costing—one that ignores yield and one that accounts for it accurately.
| Feature | As Purchased (AP) Costing | Edible Portion (EP) Costing |
|---|---|---|
| Calculation Basis | Cost is based on the total purchase price divided by the raw, as-purchased weight. | Cost is based on the total purchase price divided by the final, usable edible portion weight. |
| Accuracy | Often inaccurate, as it doesn't account for waste and trim. It underestimates the true cost of usable ingredients. | Highly accurate, providing a realistic cost per usable unit. It accounts for all waste. |
| Profitability | Can lead to underpricing menu items, which eats into profit margins unknowingly. | Ensures menu prices are set to maintain a healthy profit margin by reflecting the true ingredient cost. |
| Inventory Management | Can lead to over-ordering, as calculations are based on raw weight, not the usable amount needed for a recipe. | Facilitates precise ordering, leading to less overstocking, spoilage, and waste. |
| Waste Awareness | Minimal awareness of preparation losses, potentially hiding inefficiencies. | Pinpoints areas of high waste, allowing for better training and operational improvements. |
| Example | A restaurant buys a 10 lb bag of potatoes for $10, so they assume the cost is $1/lb. | After peeling, the 10 lb bag yields only 8 lbs of usable potato. The EP cost is actually $1.25/lb ($10/8 lbs), showing the true cost per usable unit. |
Using a Yield Test Sheet
For commercial kitchens, using a yield test sheet is standard practice for recording and analyzing yield data. A typical sheet includes fields for:
- Item: The name of the food item being tested.
- AP Weight: The initial weight of the item as purchased.
- Waste/Trim Weight: The weight of the discarded parts.
- EP Weight: The final usable weight (AP minus waste).
- Yield Percentage: The calculated percentage (EP ÷ AP x 100).
- AP Cost: The initial cost of the entire as-purchased item.
- EP Cost: The calculated cost per edible portion unit.
Conclusion: Mastering Food Yield for Kitchen Efficiency
Knowing what is the yield of a food is more than just a culinary curiosity; it's a fundamental skill for managing any kitchen efficiently and profitably. From scaling home recipes to managing a restaurant's bottom line, understanding the difference between as-purchased and edible-portion weight is critical. By regularly conducting yield tests, accounting for cooking loss, and using the data to make informed decisions, you can reduce food waste, control costs, and maintain consistent portion sizes. This knowledge transforms a simple ingredient into a fully costed, predictable component of your culinary operation. Whether you're an aspiring home cook or a seasoned professional, mastering the concept of food yield is a game-changer that ensures both quality and profitability.
The Book of Yields by Francis T. Lynch
An authoritative resource often used in culinary schools and professional kitchens is The Book of Yields: Accuracy in Food Costing and Purchasing by Francis T. Lynch. This book provides standard yield percentages for hundreds of food items, from meat and seafood to produce, serving as a reliable benchmark for chefs and managers. It allows for more accurate food costing without having to test every single item from scratch, though periodic testing is still recommended to account for supplier variations.
