How Thai Salted Eggs Are Made

What Are Thai Salted Eggs (Kai Kem)?

Thai salted eggs, known as kai kem, are duck eggs that have been cured in a salt brine until the yolk becomes firm, bright orange-red, and richly savory. The white turns clear and slightly runny, or sometimes slightly cloudy, with a very salty taste. In Thailand, they are a common ingredient and side dish, loved for the contrast between the creamy, intense yolk and milder foods.

You will most often find kai kem sold whole in markets, sometimes dyed magenta or red on the shell to distinguish them from fresh eggs. The yolk is the prize: it looks like a glossy, sunset-colored orb that can be sliced or mashed. When raw, a properly cured yolk should be firm enough to hold its shape but still slightly sticky. The aroma is mildly eggy with a clean saltiness, never sulfurous or off.

How Are Thai Salted Eggs Made?

The traditional Thai method is a wet brine cure, which is simple and reliable. It requires only duck eggs, salt, and water, though some recipes add a splash of rice wine or a few slices of galangal for extra aroma. The process takes about 14 to 21 days, depending on the egg size and desired saltiness.

Step-by-Step Thai Salted Egg Recipe

1. Choose fresh duck eggs. Wash them gently and dry completely. Check for cracks; even a hairline crack will spoil the batch.
2. Make a saturated salt brine. For every 1 liter (4 cups) of water, stir in 250–300 grams (about 1¼–1½ cups) of fine sea salt. Heat the water to help dissolve the salt, then cool completely. The brine is ready when a raw egg floats in it, showing a small circle above the surface.
3. Submerge the eggs. Place the clean eggs in a glass or ceramic jar. Pour the cooled brine over them until they are completely covered. Use a small plate or a sealed plastic bag filled with water to keep them submerged.
4. Store and wait. Seal the jar and keep it in a cool, dark place for 2–3 weeks. The longer they cure, the saltier and firmer the yolks become.
5. Test one egg. After 14 days, boil one egg for 10 minutes, cool it, and taste. If it is not salty enough, leave the rest for a few more days.
6. Rinse and store. When ready, remove the eggs from the brine, rinse them, and pat dry. Store in the refrigerator for up to a month. The yolks will continue to firm slightly over time.

Dry Salt Curing Method

Some cooks prefer a dry salt curing method: coat each clean duck egg in a thick paste of salt and water (or salt mixed with rice wine), then roll in fine salt and wrap individually in plastic. The eggs are left in a cool place for 2–4 weeks, then rinsed. This method gives a slightly firmer, drier yolk and is less messy to handle, but the brine method is more common in home kitchens.

Recognizing Quality Salted Egg Yolks

A well-cured Thai salted egg yolk should be bright orange to deep red-orange, with a glossy, slightly oily surface when raw. It should be firm enough to slice thinly without crumbling, yet creamy when mashed. The white should be clear and runny, not gelatinous. If the yolk is pale yellow and soft, the egg needs more time. If the white is rubbery and the yolk dry and dark, it has been over-cured.

How Are Thai Salted Eggs Used in Cooking?

In Thai cuisine, salted duck eggs appear in both humble and festive dishes. The yolks are often steamed or boiled, then used whole, halved, or crumbled. The whites are usually too salty to eat alone but can be chopped into fried rice or omelets to add a salty punch.

• Kai kem on its own: A classic Thai breakfast or snack is a salted egg served with khao tom (rice soup) or plain rice congee. The rich yolk balances the bland rice.
• Salted egg yolk sauce: A popular modern Thai-Chinese dish is pla muk pad kai kem—squid stir-fried with salted egg yolk sauce. The yolks are steamed, mashed, and quickly fried in butter or oil until foamy, coating the seafood with a golden, savory sauce.
• Som tam kai kem: Green papaya salad sometimes includes a halved salted egg on top, adding creaminess to the spicy, sour salad.
• Kai kem in desserts: Salted egg yolks are also used in Thai-Chinese mooncakes and steamed buns, where the salty-sweet combination is beloved.

If you cannot find duck eggs, large chicken eggs can be cured the same way, but the yolks will be smaller, paler, and less rich. The curing time may also need to be reduced by a few days. Duck eggs have a higher fat content, which gives the yolk its signature creamy, almost waxy texture and deeper color.

Comparison: Thai Salted Eggs vs. Other Preserved Eggs

Thai salted eggs are similar to Chinese salted duck eggs, but the Thai version is often less intensely salty and may have a slightly softer yolk. The brine is typically plain salt and water, without the spices like star anise or Sichuan peppercorns sometimes used in Chinese curing.

Tips for Making Thai Salted Eggs at Home

• Use very fresh duck eggs. Older eggs may have weakened shells or larger air cells, causing them to float unevenly and cure inconsistently.
• Keep everything clean. Any bacteria can spoil the brine. Use clean jars and utensils, and make sure eggs are washed and dried.
• Control temperature. Curing works best between 20–25°C (68–77°F). Too warm and the eggs may spoil; too cold and curing slows.
• Adjust saltiness. For less salty eggs, reduce brine time; for saltier, extend it. You can also adjust the salt concentration slightly (200–300 g per liter).
• Label the jar. Write the start date on the jar so you know when to test.

Substitute note: If you need salted egg yolks for a recipe right away, you can approximate the flavor by mashing cooked fresh egg yolks with a little salt and a drop of fish sauce, but the texture will be much softer and the color less vivid. True salted yolks cannot be rushed, but the simple curing process is well worth the wait.