Lotus Seed Sweet Soup (蓮子爽)

Saturday, 10 September 2011

I was buying lotus seeds when a fellow aunty shopper who was waiting for her turn asked me how the dried seeds should be cooked.

Whilst I pondered the question (and sized her up), she told me hers were still hard after soaking overnight and simmering for two hours!

Ah yes, my mother had warned me about that. I said to the lady (after deciding she wasn't trying to sell me something), "You mustn't let lotus seeds touch cold water, otherwise they won't soften. You have to wash them in hot water and, when you put them in the pot, the water must be boiling." By soaking lotus seeds in hot water which became cold overnight, she had violated the golden rule: no cold water!

What I told the lady was what my mother had told me. But, whilst I followed Mom's method, I thought her warning about cold water was just an old wives' tale. I'd never tested her theory, and I couldn't think of any reason why or how water at 30°C or thereabouts could have an effect on lotus seeds. However, judging from what the lady said, it seemed the golden rule might have some basis.

I had no idea whether the fellow shopper went home and tried my mother's method, but I came home and tried hers. I wanted to see if I could replicate her problem, and prove my mother right.

I didn't bother with soaking anything overnight. Instead, I put some lotus seeds in the slow-cooker filled with water from the tap, which took about 1¼ hours to boil. I then placed some lotus seeds in a paper pouch, and popped that in the boiling water. 30 minutes later, the lotus seeds in the paper pouch were perfectly soft and powdery whilst those that had been sitting in tap water before it was boiling were still hard. Hah, my mother was right!

The soaked lotus seeds weren't hard throughout but just on the outside. I continued the simmering and after another 30 minutes, the outer layer softened. It was, however, cracked and not powdery, and the inside was too mushy by then. The unsoaked seeds, in contrast, had a smooth exterior, and were evenly cooked and evenly powdery.

If I'd soaked the lotus seeds longer, like the lady who had left hers overnight, I think the hardened outer layer would have been thicker and harder. On the other hand, a brief rinse in cold water was actually ok provided the lotus seeds were then placed in hot water immediately.

I guess cold water had an effect on the starch in the lotus seeds' outer layer. Why and how exactly, I had no idea. But it was good to know my mother hadn't pulled a fast one on me as I dug into my bowl of Noi Ji Suan.

Noi Ji Suan, aka Lian Chee Suan in Hokkien, is a Teochew sweet soup. It's a close cousin of Tau Suan but is more glamourous because lotus seeds cost more than green beans. Why do some people think Lian Chee Suan, along with Tau Suan, is Hokkien? That's another story for another day . . . .

(Recipe for 4 persons)

120 g dried lotus seeds (1 cup), without skin
1 kettle just boiled water
8 pandan leaves, washed and knotted
6 tbsp sugar
1 tbsp water
4 tbsp sweet potato flour, mixed with 2 tbsp water

🌹 Did you know that tea made with the piths of lotus seeds helps you sleep better by removing 'heatiness' from the body? Steep a large pinch in a cup of hot water, or just pop a tiny pinch in your regular cuppa. It tastes pretty nasty, so it must be good for you.

Using the tip of a paring knife, pry lotus seeds into 2 halves (ideally without damaging your fingers). Remove piths if any. Add enough just boiled water to cover by 3-4 cm. Soak 3 minutes and drain. Place seeds in a pot with 3 cups just boiled water. Bring to a boil and simmer gently, covered, for 15 minutes. Water should be just simmering.

In a separate pot, melt sugar with 1 tbsp water over medium-high heat. Swirl till lightly coloured. Reduce heat to medium-low. Continue swirling till sugar turns light brown. Turn off heat. Keep swirling till colour is medium brown (like honey that's not very dark). With your hand to the side of the pot (to avoid the burst of steam), add ½ cup water. If sugar solidifies, heat to dissolve. Taste and make sure sugar isn't burnt. If it is, discard and repeat from 'In a separate pot . . . .'

Add sugar solution to lotus seeds. Simmer 10 minutes. Check that seeds are almost soft. If not, give them another 10 minutes. Do not overcook. Add pandan leaves. Simmer till lotus seeds are fully soft and powdery, 5-10 minutes. Discard leaves. Adjust water level and sweetness if necessary. Increase heat to medium. Stir gently and, at the same time, drizzle with sweet potato flour mixture to thicken soup. Turn off heat when soup returns to a gentle simmer. Serve hot.

🌹 If you want a really clear soup, remove lotus seeds with a slotted spoon after discarding pandan leaves. Let soup rest till sediment sinks to the bottom, 15 minutes or so. Drain soup into another pot, minus the sediment. Bring to a boil, add lotus seeds, then thicken as detailed above.


Blur Ting said...

Could it be she added sugar too early? I understand that if you do that with beans, they won't turn soft.

KT said...

Everything organic must soften if boiled long enough, eventually. Adding sugar right at the beginning would make the entire lotus seed hard rather than just the outer layer. That's not a problem if you're happy to double the cooking time. But cold water hardens LS only on the outside. If you double the cooking time, the inside of the seeds would be mush.

In the recipe above, sugar is added mid-way during cooking to slow down the softening so that the water doesn't turn too cloudy. My problem is the opposite of the other lady's! I have to stop my lotus seeds from disintegrating.

Blur Ting said...

Thanks for the explanation. You're a scientist and a cook combined!

Qqwrqwr said...

I heard from some chef that dried lotus seed in the US (usually) have been treated with a type of preservative that somehow makes the seed soften easily. When left overnight in water, those preservatives leave the seed, and thus the seeds stay hard on the outside.

KT said...

Next time I cook lotus seeds, I'll wash some and leave them wet for a few hours but not soaking in water. If they soften nicely when simmered, then what the chef said was true.

Kevin Goh said...

Everything I did from color to texture to thickness of soup is just right, It looks beautiful. You will be so proud of me. But somehow I feel that the oomph of the lotus seed flavour is missing. Has it got to do with the quality of the seed? I know this dessert well cos I am an old Teochew who happen to live in the Fort Canning area in the late 60's as a kid where the old man would ply this only dish on two basket balance on a pole on his shoulder. I just hope to relive this wonderful dessert. Kind of a comfort food. Thanks for sharing this.

kt said...

"Has it got to do with the quality of the seed?" Yes. The quality of a lot of foodstuff has deteriorated substantially in the past couple of years (in addition to the long term decline since the 60s and 70s). That's because prices have gone up so much that consumers can't absorb all of the increase, so retailers have switched to selling lower quality stuff.

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