Tub Tim Krob — Thai Red Rubies — Tub Tim Grob
This thapthim krop recipe turns crisp water chestnuts into glossy ruby-red cubes coated in tapioca, served cold in sweetened coconut milk over crushed ice. One serving is about 303 g.
Thapthim krop — also called tub tim krob, or Thai red rubies — is one of the most famous Thai desserts, sold at night markets and dessert stalls across Thailand. Its name means pomegranate seeds, because the ruby-red cubes look like the jewelled seeds of a pomegranate. The trick is the contrast: a crisp water chestnut at the centre, a chewy clear tapioca coat around it, and cold, sweet coconut milk to carry it all — a dessert built for Thailand's heat.
Pairs well with: Thai iced tea, jasmine tea, fresh tropical fruit
Provenance
Thailand
Thai Street-Dessert Classic
East & South Asia
Time Dedication
45m
25m prep • 20m cook
Batch Yield
4 Servings
451 kcal per serving
1 serving ≈ 303 g
Technical Skill
Intermediate
Medium (Coating & Timing)
Meal Timing & Digestive Fit
Breakfast
Not Advised
Lunch
Inappropriate
Dinner
Inappropriate
Snack & Tea
Ideal Light Bite
Thai Street-Dessert Classic
Photo: Iudexvivorum, CC0, via Wikimedia Commons
The Heritage Formulary
Estimated cost: Low — about $2–3 per serving at home (USD)
True thapthim krop uses crisp water chestnuts coated in tapioca starch — never flour — boiled until the coating turns clear, then served ice-cold in sweetened coconut milk.
Execution Methodology & Culinary Technique
Prep Stage: Dice the Water Chestnuts and Measure Everything
25 Mins • Dice, Colour & Measure
Peel fresh water chestnuts (or drain canned ones well) and dice them into 1 cm cubes. Dilute the red food colouring in 2 tablespoons of water. Shake the canned coconut milk, measure out the sugar and salt, and crush the ice just before serving.
Maestro Tip: Cut the cubes evenly — uneven pieces cook unevenly, and the small ones turn soft while the big ones are still opaque in the middle.
10 Mins Room temperature, about 20°C (68°F) — no heat
Toss the diced water chestnuts in the diluted red colouring until every cube is evenly ruby-red, then tip them into the bowl of tapioca starch. Toss and shake the bowl so each cube is fully coated, then lift the cubes out and shake off the loose starch — a thin, even coat is what turns clear and chewy.
If the cubes are wet, the starch clumps; pat them dry first, and coat in two batches if the bowl is crowded.
Done when: Every cube is evenly red and dusted white all over, with no bare red patches showing.
5 Mins Boiling water, 100°C (212°F)
Bring a large pan of water to a rolling boil, then drop in the coated cubes a handful at a time so they do not stick together. Boil for 2–3 minutes until the coating turns clear and glassy and the cubes float to the surface, then scoop them out with a slotted spoon straight into a bowl of cold water.
Do not overcook — a minute too long and the coating goes gummy and the crunch is gone. The cold-water bath stops the cooking at once.
Done when: The coating is clear and glossy, the cubes float, and the centres are still crisp when you bite one.
10 Mins Syrup simmering, about 100°C (212°F); coconut milk warmed gently, about 70°C (158°F) — do not boil
While the rubies cool, make the syrup: simmer 150 ml of water with 80 g of the sugar and the pandan leaf, if using, for 3 minutes until the sugar dissolves. In a second small pan, warm the coconut milk with the remaining 40 g of sugar and the salt, stirring until dissolved. Take both pans off the heat and chill the coconut milk until cold.
Coconut milk splits if it boils hard, so keep the heat low and stop as soon as the sugar disappears. Chill it well — warm coconut milk melts the ice and softens the rubies.
Done when: The syrup is clear and the sugar has fully dissolved; the coconut milk is smooth, sweet and cold, not boiling.
5 Mins Served cold, about 4°C (39°F)
Drain the chilled rubies and toss them in the cooled syrup so they stay glossy and do not stick. Divide them between four bowls, pour over the cold sweetened coconut milk, and pile the crushed ice on top.
The syrup coat keeps the rubies separate and shiny; without it they clump into one sticky mass in the bowl.
Done when: The bowls show glossy red cubes in pale coconut milk under a mound of crushed ice — serve at once, before the ice melts.
Finishing Touches & Plating
Spoon the chilled rubies into bowls, pour over the cold sweetened coconut milk, top with crushed ice, and serve at once — the rubies are at their best cold, glossy and crunchy, before the ice melts.
Nutritional Physiology & Benefits
Energy
451
kcal / serving
Protein
3g
Complete AA
Carbs
67g
Complex
Fats
21g
Healthy
| Energy | 451 kcal |
| Protein | 3 g |
| Carbohydrates | 67 g |
| Fat | 21 g |
| Fibre | 1.7 g |
| Sugar | 32.8 g |
| Sodium | 119 mg |
| Energy | 149 kcal |
| Protein | 0.9 g |
| Carbohydrates | 22.1 g |
| Fat | 7.1 g |
| Fibre | 0.6 g |
| Sugar | 10.9 g |
| Sodium | 39 mg |
Nutrition values are estimated — calculated from USDA FoodData Central values for the listed ingredients.
Vitamins & minerals: Vitamin C and potassium (water chestnuts), iron and manganese (coconut milk), small amounts of B vitamins (tapioca starch). Nutrition is estimated.
Crunch in Every Spoonful
Water chestnuts stay crisp even after cooking, so the rubies give a real crunch against the smooth coconut milk — texture, not just sweetness.
Dairy-Free by Nature
Naturally dairy-free and vegetarian — coconut milk does the creamy work, with no butter or cream needed.
Properly Filling Dessert
At about 451 kcal a serving, this is a genuinely filling dessert, not a light one — best saved for a hot afternoon when you want something substantial and cooling.
Food Pairings
To optimize nutrient absorption and elevate the sensory depth, pair with these authentic accompaniments:
Sides
Sweetened Corn or Coconut
A few extra cubes of fresh coconut or a spoonful of sweetened corn add another texture without fighting the rubies.
Vegetables
Fresh Mango Slices
A few slices of fresh mango or papaya keep the plate in the same tropical register without adding another flavour.
Drinks
Thai Iced Tea
Sweet, milky Thai iced tea echoes the coconut flavours, while jasmine tea cleanses the palate after the rich coconut milk.
Full Menus
Thai Dinner Menu
Serve thapthim krop on its own as dessert after a Thai meal such as pad thai or green curry, with Thai iced tea alongside.
Complete menu
Serve thapthim krop on its own as dessert after a Thai meal such as pad thai or green curry, with Thai iced tea or jasmine tea alongside.
Digestive Guardrails
To prevent digestive distress, sluggishness, or palate clash, avoid pairing the dish with these elements:
Eating a Full Serving Every Day
A full serving is very sweet, with about 32.8 g of sugar — best as an occasional dessert, not an everyday snack. This is general information, not medical advice.
Leaving the Rubies in Warm Liquid
Do not leave the cooked rubies sitting in hot water or warm coconut milk — they go soft and lose their crunch, which is the whole point of the dish. Chill them in cold water, then serve over ice.
General information only, not medical advice — consult a doctor for personal dietary decisions.
Who Should Eat It
Health Conditions — Adjust or Avoid
If you have a medical condition, consult your doctor before changing your diet.
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