Rajma how many whistles: cooking time, water and tips

On a stove-top pressure cooker, the rajma chawal recipe brings soaked beans up over high heat until the first whistle sounds, then keeps them on low for 20 minutes, and counts on the clock rather than on whistles. Cookers whistle at different rates, so a whistle count is only a rough guide and the clock is the better measure; the only test that matters is pressing a cooked bean against the side of the cooker with a spoon. Every bean should squash completely flat, with no firm or chalky centre left. Cooking the beans right through matters for safety as well as softness: the Dietary Guidelines for Indians explain that pulses' enzyme inhibitors, the anti-nutritional factors that stop nutrients from being absorbed, are destroyed by boiling or by pressure cooking, and a review of pulse tolerance finds no evidence that properly cooked pulses contain harmful lectins or trypsin inhibitors.

1. Pick over and rinse once. Sort out any stones or broken beans and rinse the beans in a strainer; one rinse is enough, and there is no need to scrub them.
2. Soak for 8 to 12 hours. Cover the beans with plenty of water and keep them fully covered while they swell. The full method is on how to soak rajma, quick-soak included.
3. Drain and cook in fresh water. Discard the soaking water. For every cup of dry rajma add 3 cups of fresh water and 1 teaspoon of salt to the cooker, as the rajma chawal recipe does.
4. High heat to the first whistle, then low. When the first whistle sounds, turn the heat low and set a timer for 20 minutes rather than counting whistles.
5. Let the pressure drop by itself. Switch off the heat and do not touch the lid until the pressure drops by itself; opening it early stops the cooking and risks a gush of hot water.
6. Run the spoon test. Press several beans against the cooker wall with a spoon. Each one should squash completely flat, without a firm or chalky centre left. If a bean resists, close the cooker and give the batch a couple more whistles on low, then test again.
7. Keep the cooking water. Cooked in a measured amount of water with none drained off, the beans hold on to their folate; the Dietary Guidelines for Indians say that boiling legumes in just enough water, with no draining needed, is the best way to retain their folate. The recipe stirs the beans and all their water into the masala.

Tomatoes, lemon, amchur and tamarind go in after the beans are soft: the rajma chawal recipe keeps tomato out of the pressure cooker entirely and adds it to the masala once the beans are cooked.

The rajma water ratio is 3 to 1: three cups of fresh water for every cup of dry rajma, the measure the rajma chawal recipe uses, with a teaspoon of salt per cup of beans. One cup of whole rajma weighs about 200 g, enough for four servings of 50 g dry beans. The soaking water is a separate matter: the recipe covers each cup of beans with 4 cups of water so they stay completely submerged, and drains all of it before cooking. Too little water in the cooker scorches the beans; too much leaves a thin, watery broth, though since the cooking water is kept and used, a little extra is the safer mistake.

• Skipped or short soak. A soak of just a few hours may leave the centres firm; the soak this page assumes is 8 to 12 hours. The quick-soak on the soaking page helps when time is short.
• Old beans. An old batch may be slow to soften however long it cooks, so start with a recently packed lot.
• Acid added too early. Tomato, lemon juice, amchur or tamarind in the cooker may keep the beans firm; add acidic ingredients after the beans mash soft, as the recipe does.
• Not enough water. Less than 3 cups of water per cup of beans can leave the lower beans scorched and the rest underdone; measure the water.
• The cooker itself. A weak flame, a worn gasket or a cooker crowded past half full all slow the cook; if whistles are rare or weak, fix the cooker before blaming the beans.

Whatever the cause, the rule stays the same: keep cooking, on low, until every bean passes the spoon test. Firm rajma is not a matter of taste; a review of kidney bean safety divides the toxicity into harm from lectins, saponins, phytates and protease inhibitors, and allergy from the bean's proteins, so never serve rajma raw or half-cooked.

A bitter taste can be a sign that the beans are undercooked, so the first fix is the spoon test, not more salt or spices. The second thing to get right is the soaking water: a 2018 study of Canadian pulses, common beans included, found that soaking lowered oxalates by 17 to 52 percent and lectins only slightly (0.11 to 5.18 percent), and that cooking was more effective than soaking on every antinutrient except phytic acid in common beans. So discard the soak water and cook in fresh, as the rajma chawal recipe does, and cook the beans through. The third is an old batch, which can be slow to soften; start with a recently packed lot. Do not mask bitterness with baking soda or sugar in the cooker. A systematic review of Phaseolus vulgaris lectins calls them anti-nutritional factors that can cause intestinal disorders, so cook every batch until it passes the spoon test.

The numbers are for soaked rajma in a stove-top pressure cooker; a colder kitchen or an old batch shifts them, the spoon test does not.

From here the beans go straight into the masala: the classic is rajma chawal, or the rajma curry and rajma khichdi, with more ideas in the rajma recipes roundup. How the beans should be stored, dry, soaked or cooked, is on how to store rajma, and the bean itself, its types and its nutrition, start at the rajma beans guide.

Why rajma not getting soft?

Often the soak: this page's timing assumes an 8 to 12 hour soak, and beans soaked for less may keep a firm centre. After that, check the age of the beans, keep acidic ingredients out of the cooker until the beans are soft, and measure 3 cups of water per cup of rajma. An old batch may be slow to soften, however long it cooks.

Why rajma taste bitter?

Often because the beans are undercooked, so keep cooking until every bean mashes completely soft. Throw the soaking water away and boil the beans in fresh water; a 2018 study found soaking lowers oxalates and lectins, though cooking did more. An old batch can be slow to soften, so start with a recently packed lot and keep cooking until the spoon test passes.

Can rajma be cooked without soaking?

It can, but the timing here is written for soaked beans: unsoaked beans take longer and may stay hard at the centre. The Dietary Guidelines for Indians list soaking among the established household methods that improve the digestibility of legumes, and the rajma chawal recipe builds its timing on it. If you must skip the soak, cook until the spoon test passes, adding extra water as needed.

Can rajma be sprouted?

The Dietary Guidelines for Indians give a home method for sprouting grains and legumes: soak overnight at room temperature or at least 12 hours, drain, keep the grains in a moist cloth at warm room temperature out of direct light, and expect sprouts in 1 to 3 days. The sprout should be no longer than the grain itself. Rajma is different from other sprouts in one way: cook sprouted rajma through before eating it, never raw.

Can kidney beans cause gas?

Some people get gas from rajma. Pulses carry galacto-oligosaccharides, raffinose among them, which the small intestine leaves undigested; the colon ferments them instead, and gas is released. Whether that is the real cause has lately been questioned, and a recent report found that most people who feel gassy at first get used to pulse consumption within a few weeks, provided the intake is maintained. If gas or discomfort persists, talk to your doctor or dietitian.