Cucumber Dipping Sauce for Thai Fish Cakes, and How It Differs from Ajat Relish

What the sauce should do and when to use it

The cucumber sauce served with Thai fish cakes is a sweet-sour dip. Its base is a thin vinegar-and-sugar syrup flavored with blended garlic and red chili. Fresh cucumber slices go in just before it reaches the table. In the fish-cake recipe by Pailin of Hot Thai Kitchen, the syrup carries the sweetness, acidity and garlic-chili flavor, and the cucumber, plus optional peanuts and shallots, adds fresh texture to each dip.

Use this sauce when you serve fish cakes. The cook Pim gives a closely related sauce for Thai chicken cakes, so the same style also suits other fried patties. Ajat, a Thai cucumber relish, also combines cucumber, vinegar and sugar, but it is built differently and is paired with other dishes. The comparison section below explains the difference. A sauce containing cucumber and vinegar is not automatically ajat. For fish cakes, choose the syrup-style sauce.

Ingredients for the fish-cake sauce

These quantities come from Pailin's fish-cake recipe.

• 3 cloves garlic
• 1 large red chili, a mild variety
• Thai chilies, optional, for more heat
• ½ cup sugar
• ½ teaspoon salt
• ⅓ cup vinegar (white, cane or rice vinegar all work)
• 3 tablespoons water
• To finish: cucumber slices, plus crushed roasted peanuts and sliced shallots if you like

You only need a blender and a small saucepan. Set the heat with the Thai chilies. The large red chili is mild, so leaving out the small chilies gives a gentler sauce.

Steps, in order

• 1. Blend the garlic and chilies until no chunks remain.
• 2. Put the blended aromatics in a saucepan with the sugar, salt, vinegar and water. Simmer for about 3 to 5 minutes, until the liquid becomes a thin syrup.
• 3. Take the pan off the heat and let the syrup cool. It thickens as it cools.
• 4. Check the cooled consistency. If it is too thick to dip easily, stir in water a little at a time.
• 5. Measure out only the portion you will serve. Stir the cucumber slices, and the peanuts and shallots if using, into that portion immediately before serving.

Two decisions affect the result. First, stop simmering while the syrup is still thin. Cooling will thicken it, so cooking it to a thick syrup leaves you with a sauce that is too heavy once cool. Second, keep the fresh additions out of the main batch. Adding them only to the serving portion keeps the remaining syrup free of fresh vegetables and nuts.

How to judge progress and the finished sauce

• After blending: no visible pieces of garlic or chili remain.
• At the end of the simmer: the liquid is a thin syrup, not a thick glaze.
• After cooling: the syrup is noticeably thicker than it was hot. If it is too thick, add water.
• At service: cucumber slices, and any peanuts or shallots, have just been stirred into the bowl going to the table.

A second authored version: Pim's chicken-cake sauce

Pim's accompaniment for Thai chicken cakes follows the same pattern at a larger scale. It uses 180 g vinegar, 225 g sugar, 1½ teaspoons salt, and 20 g each of red chili and garlic. The chili and garlic are blended, simmered with the vinegar, sugar and salt for about 15 minutes, then cooled. At serving time, cucumber, crushed roasted peanuts and cilantro go in. Compared with Pailin's version, Pim's has a longer simmer and adds cilantro to the garnish. Both cooks finish their sauces with fresh ingredients at service. This is one cook's variation, not a regional style.

How ajat relish differs

W. Tipsuwan of ThaiCookbook.tv gives the Thai name อาจาด, which is romanized as ajaat, ajad or achad. His relish makes about one cup. It uses ½ cup cucumber, ¼ cup red shallots, 1 to 2 Thai chilies, 2 tablespoons cilantro, ⅓ cup distilled white vinegar, 2 tablespoons sugar and 1 teaspoon salt. He heats the vinegar just enough to dissolve the sugar and salt, then cools this dressing. He adds the vegetables to the cooled dressing and lets the relish stand for about 15 minutes before serving. He pairs it with satay and yellow-curry dishes.

Feature	Fish-cake sauce (Pailin)	Ajat relish (Tipsuwan)
Usual pairing	Fish cakes	Satay and yellow-curry dishes
Sugar to vinegar	½ cup sugar to ⅓ cup vinegar	2 tablespoons sugar to ⅓ cup vinegar
Garlic and chili	Blended and simmered into the syrup	No garlic; Thai chilies added fresh with the vegetables
Cooking	Simmered 3 to 5 minutes into a thin syrup	Vinegar heated only to dissolve sugar and salt
Vegetables	Cucumber, optional peanuts and shallots, stirred in right before serving	Cucumber, shallots, chilies and cilantro, left in the dressing about 15 minutes
Result	Syrupy sweet-sour dip	Sharper, thinner pickled relish

In practice, the fish-cake sauce is a cooked syrup that gets fresh additions at the last moment. Ajat is a lightly sweetened vinegar dressing in which the vegetables steep briefly before serving. If you follow an ajat recipe for fish cakes, expect a much less sweet, more acidic, thinner accompaniment than the documented fish-cake sauce.

Illustrative example: a sauce selection card

Here is one way to keep the two sauces straight if you cook both. Make a short card for each that records: the dish it accompanies, the cook whose version you follow, the syrup or dressing ingredients, the fresh additions, and when those additions go in. For fish cakes, the card would read: fish cakes; Pailin; garlic, chilies, sugar, salt, vinegar and water simmered into a thin syrup; cucumber with optional peanuts and shallots; added to the serving portion just before serving. A separate ajat card would read: satay or yellow-curry dishes; Tipsuwan; vinegar heated with sugar and salt, then cooled; cucumber, shallots, chilies and cilantro; added to the cooled dressing about 15 minutes ahead.

Substitutions

• Vinegar: Pailin accepts white, cane or rice vinegar for the fish-cake sauce. Tipsuwan specifies distilled white vinegar for ajat.
• Heat: add or leave out the Thai chilies in the fish-cake sauce. The large red chili is the mild base.
• Garnish: peanuts and shallots are optional in Pailin's version. Pim's version adds cilantro.

Food safety

Once cucumber, shallots, peanuts or cilantro are stirred in, treat the sauce as a perishable cold food. The USDA advises keeping cold perishables at 40°F or below. Refrigerate them within two hours, or within one hour when the surrounding temperature is above 90°F. These rules do not make the finished dip safe to keep at room temperature. The recipes also give no storage time for the syrup base. The practical approach is to add the fresh ingredients only to what you will serve, and to refrigerate any assembled leftovers promptly.