Onions are a kitchen staple used in many savory dishes, but cutting them can sometimes bring tears to the cook’s eyes. The burning sensation and tearing are caused by the onion releasing a sulfur gas when its cells are damaged during cutting. Some cooks have long debated which end of the onion to cut off first to minimize irritation.
Does it matter which end of an onion you cut first?
The simple answer is – yes, it does make a difference! Cutting the top (stem) end first helps reduce tears while chopping. This is because the onion’s sulfuric compounds that cause irritation are more highly concentrated in the root end versus the stem end.
Why Cutting the Stem End First Helps
Here are a few key reasons why cutting the stem end first can help prevent tears:
- Fewer irritant gases released initially – There are less irritating compounds present near the dry stem end versus the moist root end. Cutting the top first results in a more gradual release of the tear-inducing gases versus all at once if cutting the root first.
- Avoids cutting into the root early on – The root end contains the highest concentration of sulfuric irritants. Removing the stem end first means you can chop and dice the majority of the onion before ever hitting the concentrated irritants in the root.
- Keeps root end intact longer – Leaving the root end together longer maintains the onion’s structural integrity. Once you cut into the root, more tear-inducing gases are rapidly released. Cutting the top first delays this concentrated release.
The takeaway is that by cutting into the milder stem end first, you can chop and prepare much of the onion before ever hitting the most potent tear-inducing compounds found in the root end. This results in less overall irritation when prepping onions.
What causes onions to make you cry?
When an onion is cut, cells are broken open releasing sulfenic acids which then mix with the air to formSyn-propanethial-S-oxide. This gas vapor wafts towards your eyes and reacts with the water in tears to form sulfuric acid. The sulfuric acid irritates the nerve endings in your eyes, causing stinging and watering.
Onions contain the highest concentration of sulfenic acids at the bulb end (the root) and lower amounts in the stem end. This makes the root end more likely to cause crying when cut.
Other tips to prevent onion tears
While cutting the stem end first can greatly reduce tears, here are a few other useful tips:
- Chill the onion in the fridge for 30 minutes before cutting – The cold temperature makes the gases less volatile.
- Use a super sharp knife – A sharp clean cut minimizes cellular damage and formation of the tear-inducing compounds.
- Cut under running water – Washing away the gases as you cut prevents them wafting towards your eyes.
- Use a fan – Having airflow directed away from you keeps the gases from reaching your face.
- Wear goggles – Protects eyes from any onion vapors.
What’s the best way to cut an onion?
Follow these steps for easy tear-free onion chopping:
- Trim the stem end off first.
- Make root to stem vertical slices, leaving the root end intact.
- Make horizontal cuts from stem to root.
- Finally, slice the onion in half vertically through the root.
This method delays exposing the potent sulfuric acid compounds in the root while methodically chopping and dicing the milder stem end.
Onion Chopping Techniques
Different dishes call for different onion cuts. Here are some common ones:
Dice
Diced onions are small uniform cubes, around 1⁄4 inch. Good for sautéing.
- Trim ends and peel.
- Cut onion in half stem-to-root.
- Make vertical slices from stem to root.
- Make horizontal slices across.
Chop
Chopped onions are somewhat uneven, larger pieces. Good for soups, stews, etc.
- Trim ends and peel.
- Cut onion in half stem-to-root.
- Hold halves together and slice across.
- Separate slices and chop coarsely.
Minced
Minced onion almost resembles a paste. Ideal for mixing into dressings, spreads.
- Trim, peel, and halve onion.
- Slice onion very thinly.
- Cut slices into 1⁄8 inch pieces.
- Chop finely with knife tip.
Slivered
Slivers are thin, elongated oval slices. Work well fried or as garnish.
- Trim ends and peel.
- Cut onion in half stem-to-root.
- Lay flat side down and slice thinly.
Onion Storage Tips
Follow these guidelines for keeping onions fresh longer:
- Store in a cool, dark, well-ventilated area.
- Don’t store near potatoes – they will cause spoiling.
- Place in loosely woven basket, net bag, or open bowl.
- Keep dry onions separate from shallots and scallions.
Properly stored dry onions can last 2-3 months while shallots and scallions may only last 1-2 weeks. Look for signs of spoiling like mold, darkening, or sprouting. Any sprouted or spoiled onions should be discarded.
Using Onions
Onions are very versatile for cooking. They add flavor, depth, and complexity to many savory dishes.
Raw Onions
Raw onions have a strong, pungent flavor. They are often used as:
- Toppings for burgers, pizza, sandwiches
- In salads, salsas, relishes
- As garnishes and toppings
Cooked Onions
Cooking mellows the sharpness of raw onions. Cooked onions are popular in:
- Soups, stews, curries, stir fries
- Sautés and frittatas
- Casseroles and baked dishes
- Onion rings and fried onions
Cooking brings out onions’ natural sweetness. Red or yellow onions are best for cooking while white onions are often used raw.
Popular Onion Types
There are many onion varieties to choose from. Here are some common ones:
Yellow Onions
- Most widely used onion
- Moderate, all-purpose flavor
- Crisp texture
- Good both raw and cooked
White Onions
- Very crisp and pungent
- Often used raw in salsas, salads
- Also good roasted or grilled
Red Onions
- Mild, sweet flavor
- Purple color adds vibrant touch
- Excellent grilled or roasted
- Also used raw
Shallots
- Small, elongated bulbs
- Delicate, slightly sweet flavor
- Used raw or cooked
- More expensive
Green Onions
- Long green stalks with white bulb
- Very mild, fresh flavor
- Often used raw as garnish
- Also used cooked
There are so many great onions to experiment with in the kitchen. Let your dish and preferences guide you in selecting onions to cook with.
Onion Nutrition Facts
Onions are very nutritious, providing key vitamins, minerals, and other beneficial plant compounds. Here is the nutrition breakdown for a 3.5 ounce raw onion serving (about 1 medium onion):
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 44 | 2% |
| Carbohydrates | 10 g | 4% |
| Fiber | 1.7 g | 7% |
| Sugar | 5 g | |
| Protein | 1 g | 2% |
| Vitamin C | 11% | 11% |
| Vitamin B6 | 10% | 10% |
| Folate | 6% | 6% |
| Manganese | 7% | 7% |
As shown, onions provide vitamin C, B6, folate, and manganese. They are low calorie and provide dietary fiber. Onions also contain beneficial plant compounds like quercetin, anthocyanins, and organosulfur compounds.
Health Benefits of Onions
Eating onions regularly may provide these health benefits:
- Reduce inflammation – Quercetin acts as an anti-inflammatory.
- Boost immune function – Onion’s sulfur compounds support immunity.
- Improve bone health – Manganese aids bone formation.
- Promote gut bacteria – Prebiotic fibers feed beneficial gut bacteria.
- Reduce heart disease risk – Quercetin lowers blood pressure and cholesterol levels.
- Potential anticancer effects – Quercetin may help inhibit cancer cell growth.
More research is still needed on onions’ role in preventing chronic conditions like cancer and heart disease. But their antioxidant, anti-inflammatory, and prebiotic effects contribute to an overall healthy diet.
Risks and Precautions
Onions are safe for most people but there are a few precautions:
- Allergies – Some people are allergic to onions and can experience reactions. Severe onion allergy is rare.
- Medication interactions – Onions contain vitamin K which can interact with blood thinners like warfarin. Patients on blood thinners should keep vitamin K intake consistent.
- Digestive problems – Some report gas, bloating or irritation with raw onions, especially in those with IBS. Cooking onions can reduce digestive issues.
- Nutrient deficiencies – Sulfur compounds may interfere with absorption of iron and other minerals. This is usually only an issue for those already deficient.
Consult your healthcare provider about any concerns. For most people, onions can be safely enjoyed as part of an overall nutritious diet.
Conclusion
Chopping onions can cause some tears, but cutting the stem end first and using a sharp knife can help minimize eye irritation. Onions provide a great flavor boost to many savory dishes, and also deliver beneficial nutrients and plant compounds. Including onions as part of a vegetable-rich diet can provide anti-inflammatory effects and other health perks. Enjoy onions raw or cooked, and select different varieties to take advantage of their diverse flavors and colors.