Cooking Water: Keep or Throw? Rice Pani, Daal Water, Sabzi Stock
Keep the daal water and the sabzi water, because they hold vitamins and flavour that the pot just pulled out of your food. Rice water is the one to think about: it is mostly starch, and when you drain rice on purpose to cut arsenic, the arsenic is in that water, so don’t drink it or feed it to babies.
The short version
- Daal water: keep it, use it in the daal, a soup or the atta.
- Sabzi boiling water: keep it as stock, unless the water is from spinach and someone at home has had oxalate kidney stones.
- Rice maand (starchy water): fine to use when rice was washed well; pour it away when you drained rice to lower arsenic.
- Rajma or chana soaking water: throw it away.
- Stored stock: fridge within 2 hours, use in 3 to 4 days, boil hard before using.
What leaves the food and goes into the water
Boiling is a slow wash. Some vitamins dissolve in water, and those are the ones that walk out of your vegetables, vitamin C and the B group (folate, thiamine and friends), with minerals such as potassium following close behind, so the more water, the longer the boil and the smaller you chop, the more ends up in the pot instead of on your plate.
Fat-soluble things stay put. Beta carotene in gajar, for example, barely leaves carrots in plain water, which is why the carrot-cooking water looks pale even after twenty minutes.
So the water you’re about to pour down the sink is a thin, lightly salty soup of what you paid for. For a deeper look at which vegetables gain and lose from cooking, see our piece on raw vs cooked vegetables.
Daal water: the easiest keep
Daal ka pani, the thin liquid skimmed off the top of boiled masoor or moong, is an old sick-room food in desi homes, given with a pinch of salt and zeera to someone who can’t face a full meal. That tradition makes sense as gentle food and fluid for a tired stomach, easy to sip, lightly salted and warm, and it earns its place on those days as food rather than as anything stronger. It isn’t medicine.
What’s in it? Quite a lot. Some protein, a bit of starch, potassium and B vitamins, and the flavour of the daal. Pouring it off to make a “thicker” daal and then adding fresh water back in is the one habit worth dropping, because you lose the good part and keep the work.
The white froth that rises when daal first boils is a different thing. It’s mostly protein and saponins (soapy plant compounds) trapped in bubbles. Harmless.
Rice water: starch, and the arsenic question
Rice is the one grain that takes up a fair amount of arsenic from flooded paddy soil, and some of it dissolves out when rice cooks in lots of water. That’s why the pasa chawal method (boil rice in about 6 parts water, then drain) leaves less arsenic in the rice than the absorption method, where every drop of water goes back into the grain. We compare the methods in rice arsenic: draining vs absorption vs cooker.
Here’s the catch. If draining is the point, the drained water is where the arsenic went. Drinking it every morning as a “rice water hack” undoes the reason you drained. Babies and toddlers shouldn’t get it at all, because their small bodies take a bigger dose per kilo.
Maand has a use when arsenic wasn’t the goal: a spoon or two thickens a thin shorba, and it starches a cotton dupatta nicely. As a food it’s mostly starch and water, so a little is perfectly fine, but nothing about it makes it a tonic worth drinking by the glass. Keep it modest.
The Bacillus cereus rule
Starchy water left warm on the counter is the classic setting for Bacillus cereus, the germ behind reheated-rice food poisoning. Its spores survive boiling. Every time. Cool maand fast, keep it in the fridge and use it the next day, or don’t keep it at all.
Sabzi water and home stock
The water from boiling aloo, gobi, gajar, matar or lauki is ready-made stock. Use it to knead atta for softer rotis, to thin a curry, or as the base of a quick soup. Taste first.
A simple scraps stock is even better value. Onion ends and skins, carrot tops, coriander stems, the tough ends of gobi and a few peppercorns simmered for 30 to 40 minutes give a clean, sweet broth. Wash scraps well first, because peels carry soil and pesticide residue, and skip anything mouldy, slimy or bitter, since a stock only ever tastes as good as the worst thing that went into the pot.
When to pour it away
- Rajma, lobia and chana soaking water: discard it. Kidney beans must then be boiled hard for at least 10 minutes before a slow simmer.
- Spinach and chard boiling water: oxalates leach into it, which is the point of boiling if someone has had calcium oxalate stones. Keeping it would put them back.
- Water from green or sprouted potatoes: cut those parts away before cooking; better still, don’t use a very green potato.
- Anything cooked in a pot that burnt: the smoky, bitter taste spreads to everything.
- Stock left out overnight: throw it out, even if it smells fine.
Anyone at home has kidney disease and has been told to limit potassium: boiling vegetables and discarding the water is sometimes advised on purpose in that case, so follow the renal team’s plan rather than this page. Babies under 1 should not get salted stock or drained rice water, and weaning food gets no added salt at all. Anyone with a history of kidney stones can ask the doctor whether spinach water is worth keeping.
How to store cooking water safely
- Strain the water into a clean steel or glass container while it’s still hot.
- Cool it fast: stand the container in a basin of cold water for 15 to 20 minutes, stirring once or twice.
- Get it into the fridge within 2 hours of cooking, lid on.
- Use daal water and vegetable stock within 3 to 4 days. Use rice maand by the next day.
- Freeze stock in ice-cube trays or 250 ml tubs for up to 3 months. Label the date.
- Before using, bring it to a full rolling boil for at least a minute, not just warm.
- If it smells sour, looks cloudy when it was clear, or has a film on top, throw it away.
Myth: boiling water “kills” all the vitamins, so it’s useless
Heat does break down some vitamin C, but most losses in a boil are leaching, not destruction. Nothing is lost until you pour the water away. That’s the whole case. Pressure cooking loses less again, because there’s less water and the time is short, which our note on pressure cooker vs slow cooking goes into.
Myth: rice water is a health drink
Rice water trends online for skin, hair and weight. As a drink, it gives starch and a trace of B vitamins, which a plate of rice already does, and nothing in it is special enough to justify drinking drained water on purpose, and the arsenic point above makes the drained kind a poor daily habit.
Nothing leaves your plate until you pour the pot down the sink.
More plain answers on what cooking does to food live under Kitchen Science, Honestly.
Cooking water questions people ask
Is it good to drink rice water after cooking?
Not as a habit. It’s mostly starch with a trace of vitamins, and if the rice was drained to cut arsenic, the drained water holds that arsenic. A spoon or two in a soup from well-washed rice is fine.
Should daal water be thrown away?
No. Daal water carries protein, potassium, B vitamins and flavour. Keep it in the daal, or use it to knead atta or thin a soup; only skim the foam if you want a clearer look.
Can vegetable boiling water be used for roti dough?
Yes, and it makes softer rotis. Let it cool to warm and cut the salt in the atta if the boil was salted, then use it the same day or keep it in the fridge.
Does draining rice remove nutrients?
Some. Draining pulls out a share of the B vitamins, especially in fortified rice where vitamins are coated on the grain, and it also removes more arsenic, which is the trade most families accept for daily rice.
How long can homemade vegetable stock stay in the fridge?
Three to four days, in a covered container, if it was cooled and chilled within 2 hours of cooking. For longer, freeze it for up to 3 months and boil it hard before use.
Is rice water (maand) safe for babies?
Drained rice water is best avoided for babies and toddlers because of arsenic. Babies under 6 months need only breast milk or formula, and older babies are better off with properly cooked mashed rice than its water.
Should rajma soaking water be used for cooking?
No. Throw away the soaking water, rinse the beans, then boil them hard for at least 10 minutes before simmering; that hard boil is what makes kidney beans safe.
Why does daal make white foam when boiling?
The foam is protein and saponins caught in steam bubbles. It’s harmless. Skim it for a cleaner pot, or add a few drops of oil to stop it boiling over.
Is spinach water safe to drink?
For most people, yes, in normal food amounts. People with a history of oxalate kidney stones may prefer to discard it, since boiling moves oxalate from the leaves into the water.
Can stock be left out overnight to cool?
No. Leaving it warm for hours lets bacteria grow, and reboiling won’t undo every toxin they make. Cool it fast in a cold water bath and refrigerate within 2 hours.
Does pressure cooker water have nutrients?
Yes. Usually less is lost than in open boiling because there’s less water and a shorter time, and whatever is in the cooker water should go into the dish.