Tub Tim Krob Recipe: The Authentic Thai Red Rubies Dessert

Tub tim grob or thapthim krop is one of the most well-known Thai desserts, made of water chestnuts soaked in red food dye, then boiled in tapioca flour. Because of its distinctive red look, the dessert is also called pomegranate seeds or rubies. The dish's unique flavors make it exciting to eat and its many textures make it a delight that’s hard to ignore. This dessert is also rather easy to make. So follow this most delicious dessert recipeand learn how to make tub tim grob in your very own kitchen, and give your guests a taste of the best that the Thai cuisine has to offer.

Tum Tim Krob: Ingredients For The Red Ruby Dessert

Choosing The Best Water Chestnuts

For a perfect Tub Tim Krob, canned water chestnuts are often considered the best choice for that crunchy consistency. Alternatively, one may also opt for fresh water chestnuts for a fresh and natural sweetness. However, peeling them makes the process more laborious.

Tapioca Flour vs. Starch

The traditional Tub Tim Krob relies on tapioca flour only. It is never recommended to replace it with cornstarch. It is the tapioca starch that creates the signature chewy, jelly-like coating around the water chestnuts. Cornstarch often results in a soft, chalky, or powdery texture instead due to a lack of elasticity.

Ingredients

For the red rubies:

• 100 gm canned water chestnuts
• 80 gm tapioca starch, or more as needed
• 1 Tbsp red yeast rice powder or use few drops of red food coloring + 2 Tbsp water
• 100 ml hot water (to mix with red yeast rice powder), omit if you use red food coloring
• ice water
  
  

For the blue rubies:

• 100 gm canned water chestnuts
• 2 Tbsp water
• 80 gm tapioca starch, or more as needed
• 30 pieces dried blue pea flowers or use few drops of blue food coloring + 2 Tbsp water
• 100 ml hot water (to soak the flowers), omit if using blue food coloring
• ice water

For the coconut milk sauce:

• 250 ml coconut milk
• 100 gm sugar
• 100 ml water
• ⅛ tsp salt
• 2 pandan leaves knotted
  
  

How to Make Tub Tim Krob: Step-By-Step Guide

Preparing the rubies

• First, prepare the red and blue rubies. Peel canned water chestnuts and dice them into half-inch pieces. Bring out two bowls, one for the red rubies and one for the blue rubies.
• If you’re using natural coloring, mix the red yeast rice powder with hot water in a bowl and stir well until it dissolves. Then strain the mixture and add half the water chestnuts. Let them soak in the red water for about 30 minutes. Now soak the blue pea flowers in hot water for about 30 minutes. Then discard the flowers and collect the blue liquid. Soak the remaining water chestnuts in the blue water for about 30 minutes.
  OR
  If you’re using food coloring, add 2 spoons of water and about two drops of each food coloring in different bowls. Add half the water chestnuts into the red bowl and the other half into the blue bowl. Set aside to let them soak.

 Making The Coconut Syrup 

• While they soak, prepare the coconut milk sauce. Place the coconut milk, sugar, water, salt and pandan leaves in a pan on medium heat. Let it simmer for about five minutes, but be careful to ensure it doesn't reach a boil. Once simmering, turn off the heat and place it in the fridge to chill until ready to serve.

• Now, place water in a large pot over medium heat and let it come to a boil. Drain the water chestnuts out of the red and blue liquids. Sprinkle ⅓ of the tapioca flour over the red rubies and another ⅓ over the blue rubies. Toss them to ensure each ruby is properly coated with the flour. Then add more flour to each bowl and toss it again to thoroughly coat all the rubies. Then sieve the rubies to remove any excess flour. The rubies should look white from the flour coating.
• Now gently drop the rubies in the building water and stir well to prevent the rubies from sticking to each other. The rubies will eventually rise to the top of the water. Let it continue cooking for another five minutes. If there are a lot of white specks, they are not fully cooked yet. You’ll know they are done cooking when the rubies look transparent.
• In the meantime, prepare a bowl with water and ice in it. Once done, remove the rubies from the boiling water using a sieve and immediately transfer them to the bowl with the ice-cold water. This will stop the cooking process.

• To serve, add some of the red and blue rubies to the plate, then ladle the chilled coconut milk sauce over them. Add ice shards on top. Serve immediately.
  
  

Tips For The Crispiest Rubies

• For the best results, it is crucial to prepare the chestnuts well. It is always recommended to slice them into clean pieces instead of smashing them.
• While adding the rubies, make sure the water is boiling. Otherwise, the tapioca starch tends to wash away instead of sealing.
• An ice bath is crucial to create that thermal shock for the rubies, as it creates the glossy texture. It is always best to keep it ready on time.
• To experience the best version of the dessert, make sure the rubies are made on the day they are served. Refrigerating them often causes the tapioca coating to harden and lose its delicate texture.
• You can add some coconut milk while serving and add ice cubes on top, and serve in a glass, much like a falooda.

Serving Suggestions & Variations

• Make sure the rubies are added to the coconut milk just before serving. If they are kept in the liquid for long, they tend to become soggy.
• Consider adding a little extra sweetness to the coconut syrup. This is needed because the dessert is always served with crushed ice. If the coconut syrup is not sweet enough, the melting ice will dilute the sweet taste completely.
• For this classic Thai dessert, one can go creative with natural dyes like butterfly pea flower (blue), pandan (green), or turmeric (yellow) for the rubies. The coconut milk can be made more tasty with toppings like jackfruit, corn, or beans.