Onion Varieties: How to Select and Cook Onions for Best Flavor

Ethan Chlebowski

Onion Varieties and Cultivation [00:02:43]

• Onions belong to the allium genus, part of the lily family, known for their strong sulfury aromas that deter animals.
• Bulbing and non-bulbing alliums exist, with the video focusing on bulbing alliums (Allium cepa) such as white, yellow, red, sweet, and shallots.
• Bulbing onions are biennial plants with a two-year life cycle.
  • In the first year, they grow green tops and a small bulb.
  • In the second year, they use stored energy to produce green tops, forming thick fleshy layers in the bulb.
• Pearl onions, cipollini, and baby onions may be onion sets grown for a single season or harvested early.
• Harvesting occurs when green tops wither or the plant flowers, signifying the bulb is ready.
• Curing the harvested bulbs in a dry, ventilated area for 2-4 weeks forms a protective papery skin.
• Global onion production reaches 105 billion pounds annually, with Libya having the highest per capita consumption at 66.8 lbs.

Onion Varieties and Flavor Profiles [00:07:06]

• Yellow Onions: The most common type in the US, accounting for 87% of production.
• Sweet Onions: Varieties of yellow onions like Vidalia and Walla Walla are milder and considered sweeter; Vidalia onions must be from Georgia.
• Red Onions: Estimated at 8% of US production, commonly used in Indian cuisine, and provide vibrant color when pickled.
• White Onions: About 5% of US production, often the choice for Mexican cuisine.
• Shallots: Considered part of Allium cepa since 2010, they resemble a cross between garlic and bulbing onions, with cloves like garlic.
  • Have higher carb and lower water content, influencing their flavor when cooked.

Factors Influencing Onion Flavor [00:10:45]

• Flavor comprises taste, aroma, texture, sight, physical, and human elements.
• Raw onions can be overwhelming, but with lime juice, tomatoes, cilantro, and pepper, they become palatable pico de gallo.
• Sautéing onions removes pungency, developing a savory aroma, while caramelizing them creates deep sweetness.
• Eight different tests were conducted to analyze onion flavors in raw, sautéed, and caramelized states.
• White, yellow, and sweet onions taste similar raw; red onions have the most oniony aroma, and shallots are the most pungent.
• There are five main tastes: sweet, salty, sour, bitter, and umami, with raw onions being relatively neutral.
• Onions consist primarily of water, carbohydrates, and protein, with flavor stemming from protein and carbohydrate composition.

  

  • The yellow, white, and sweet onions have similar compositions, while red onions have lower water content, and shallots have the least water content.
• Caramelized onions result from both the Maillard reaction (protein molecules) and caramelization (sugar molecules).
• Three key takeaways:
  1. Onion varieties have unique aromas from volatile organic compounds.
  2. Flavor intensity depends on the amount of cell damage.
  3. Aroma molecules are volatile and change over time.

Raw Onion Tests and Observations [00:22:08]

• Pico de Gallo Test: A triangle test was conducted using pico de gallo made with white versus yellow onions. It was difficult to discern a difference, suggesting other factors like tomato ripeness and cilantro levels play a bigger role.
• Italian Hoagie Test: Red versus sweet onions were tested in Italian hoagies. It was difficult to taste the difference between red and sweet onions due to the other ingredients present.
• Cooking with fat helps to release volatile organic compounds, making the aromas more noticeable.

Sautéed Onion Flavors [00:29:57]

• 50g of diced onions were added to 10g of oil and sautéed for 8 minutes before tasting them. In sautéed onions, pungency diminishes, with the fat soluble aromas being released.
• Shallot Chopped Cheese Test: Shallots and sweet onions were used to make chopped cheese sandwiches, revealing a clear preference for shallots due to their balanced flavor with the beef.
• Key questions to consider when using onions: Is color important? What level of aroma is desired? How much pungency is needed?

Caramelized Onions [00:39:26]

• Caramelized onions involve two key reactions: caramelization (sugar molecules) and the Maillard reaction (protein and sugar molecules).
• Onions were cooked in an oven at 350°F, with samples taken every 10 minutes up to 60 minutes to assess flavor changes.
• A YouTube poll showed varied preferences for caramelization times.
• A test was conducted to see if onions could be caramelized in 10 minutes on high heat in a carbon steel pan.
• After 7 minutes, some water was added for the final three minutes, although the flavor lacked the depth of long-cooked onions, it still resulted in good flavor for the short time frame.
• Further questions: What would a sprinkle of sugar added do? Is the baking soda method necessary? What is the optimal cook time?
• The best onion to keep at home depends on personal preferences, although red onions were recommended for their pungency and aroma.