Both mushrooms and onions are common ingredients used in many savory dishes. However, they have different properties when it comes to cooking. The main factors that affect cooking time for vegetables are water content and texture.
Water Content
Onions have a higher water content than mushrooms. According to data from the United States Department of Agriculture (USDA), 100g of raw onion contains 89.11g of water, while 100g of raw white mushrooms contains 90.21g of water.
The high water content means moisture needs to evaporate before the onion starts browning and caramelizing. Mushrooms have a bit less moisture, so they will start browning sooner.
Texture
Raw onions have a crisp, dense texture that softens over time during cooking. Mushrooms have a more delicate, porous structure. This porous structure allows moisture to evaporate quickly during cooking.
Onions also have cell layers that break down at different temperatures. So onions seem to cook at a gradual pace. Mushrooms offer less resistance to cooking due to their softer cell structure.
Cooking Methods
The cooking method impacts the time it takes to cook mushrooms and onions.
Sautéing
If mushrooms and onions are sautéed in a little oil over medium-high heat, the mushrooms will cook faster. Their moisture evaporates quickly, causing them to brown within 5-10 minutes. Meanwhile, onions need 15-20 minutes of sautéing to turn translucent and browned.
Roasting
Roasting uses dry heat to cook vegetables in the oven. Mushrooms again cook faster, being done after 15-20 minutes at 400°F. Onions take 30-40 minutes to caramelize and turn fully tender when roasted.
Simmering
Simmering involves cooking vegetables in or with liquid over low heat. This moist environment causes onions to cook faster than mushrooms. Whole onions in soup may be tender after 20-30 minutes of simmering. Mushrooms, especially larger ones, often take 30-40 minutes to become fully tender when simmered.
Grilling
The intense dry heat of grilling also cooks mushrooms faster than onions. Sliced mushrooms can be perfectly grilled in just 8-12 minutes. Onions take 12-15 minutes on the grill to char and soften.
Size and Shape
The size and shape of the vegetable pieces also impact cooking time. Smaller pieces cook faster due to greater surface area exposure to heat. Uniformly sliced onions and mushrooms will cook quicker than large, whole vegetables.
Onion Types
The variety of onion also makes a difference. Red and yellow onions have a higher moisture content than white onions. Sweet onions like Vidalias also have more moisture. These types will require longer cooking than white, yellow, or red onion varieties.
Mushroom Types
Portobello and other large mushroom caps will take longer to cook than thin sliced cremini or white button mushrooms. Morel, chanterelle, and other specialty mushrooms with different shapes may cook at different rates too.
Conclusion
In most cases, mushrooms cook faster than onions. Their lower moisture content and delicate texture mean they brown quickly when exposed to heat. Onions have a more dense structure and higher water content requiring evaporation during cooking.
However, the specifics of the cooking method, size of the pieces, and varieties of each vegetable determine the exact timing. Under moist cooking methods or with larger pieces, onions may occasionally cook as quickly or slightly faster than mushrooms.
To summarize:
| Cooking Factor | Favors Faster Cooking |
|---|---|
| Water content | Mushrooms |
| Texture | Mushrooms |
| Cooking method | Mushrooms for drier heat, Onions for moist heat |
| Size and shape | Smaller, uniform pieces |
| Onion variety | White onions over sweet onions |
| Mushroom variety | Smaller mushroom types |
Knowing these factors can help cooks better time the addition of mushrooms and onions to dishes based on how long they take to cook. With proper preparation and cooking methods, both mushrooms and onions can be made tender and flavorful.