Recipes for 薑汁撞奶 usually specify the use of old ginger but I've succeeded and failed before with both old and young ginger. It's not the age that matters, but the white stuff you see in the photo above. That's the starch in the ginger juice that solidifies the fats and proteins in milk, turning it into a custard. I've come across old ginger which doesn't have much of it, and also young ginger which has lots. How do you tell if the ginger has lots or not? I don't know. But I do know that if you don't see a thick layer of starch after letting the ginger juice rest a few minutes, you should forget about 薑汁撞奶 and make teh halia instead.
How much ginger juice should there be? The ratio of juice to milk should be 8-10. If there's too little ginger juice, there'd be naturally too little starch and the milk wouldn't set. Too much is bad too unless some of the liquid part of the ginger juice is removed.
The way you add the milk to the ginger juice is critical to the success of the pudding. First, stir the starch sitting in the bottom of the bowl. Stop stirring, then pour the right amount of milk into the bowl in one go. It has to "crash" into the ginger juice, as the Cantonese name for the dessert says. Because the milk fats and proteins start solidifying once the milk hits the ginger starch, the turbulence in the bowl should be just sufficient to mix the starch and milk, then stop asap or the curds being formed would be broken up.
The temperature of the milk has a huge impact on how firm the pudding is. If it's too hot or too cold, the starch may not set at all. The good news is, ginger flavoured milk is quite nice! On no account use this ginger flavoured milk to make ginger tea. If you do, you'll regret it.
The ideal temperature is 75-80°C, i.e. hand-hot. That's for cow milk, btw. For buffalo milk – which is what's used in the pudding's hometown in China – I suspect the ideal temperature may be different (lower?) because it has more fats and proteins than cow milk and, hence, sets more firmly.
If you want the pudding to be as firm as possible, don't add any sugar to the milk. Instead, make some sugar solution and drizzle it on the pudding like how you'd eat tau huay (豆花).
Finally, because you sooooo need a video to show you how to chop ginger and warm up milk, here it is:
|GINGER MILK PUDDING (薑汁撞奶) |
(Recipe for 2 persons)
360 ml full-fat fresh milk
4 tsp sugar
40 ml freshly squeezed ginger juice, divided equally between 2 serving bowls
let ginger juice rest 5 minutes; check amount of starch in bottom of bowls; if there isn't much, do not proceed
Heat milk and sugar till hand-hot. Stir ginger juice. Stop stirring, then pour 180 ml milk in one go, quickly, into each bowl. Leave for 10 minutes without moving bowls. Serve.