Saag is a Hindi word that is used to refer to herbs and green leafy vegetables. Greens such as sorrel, mustard greens, kale, fenugreek leaves, lamb's-quarter and colcassia leaves are all referred to as saag. Palak refers to a specific green leafy vegetable: spinach, which can also be referred to by the generic term "saag." Palak can be used in any recipe that calls for saag, and other forms of saag can be substituted when palak is specifically requested. The term saag is also used to refer to a dish of greens sautéed with oil and spices.
Spinach, or palak, is a cool-weather crop that can be planted in both the spring and the autumn. It contains vitamin A, iron, calcium and folic acid. Spinach can be harvested as soon as the leaves are about 7.5 cm (3 inches) long. Raw spinach has a sharp, slightly peppery taste. Cooked spinach can develop a slightly metallic aftertaste. This aftertaste is masked when the palak is sautéed in oil with garlic and spices.
Sarson (mustard greens)
Mustard greens are a common saag used in Punjabi cuisine. The greens are more pungent than palak and have a slight mustard flavour that also has a hint of horseradish. Mustard greens are more substantial than spinach and take longer to cook and soften. Purées made with spinach are thinner than those made with mustard greens. Spinach and mustard greens are sometimes combined in the same dish to balance out the flavours, creating a more flavourful dish than is made with just spinach, and a more mellow dish than if only mustard greens were used.
Sorrel, sometimes also called sour grass, is a herb that is often substituted for spinach. This saag contains oxalic acid, like spinach, which can give it a slightly metallic taste when cooked. Sorrel has a pungent, somewhat lemony flavour that is more bitter than spinach (palak). The leaves are small and very tender. Sorrel has a tendency to dissolve when cooked, producing purées that are thinner and more watery than those made from palak.
Methi (fenugreek leaves)
Fenugreek, or methi, are a saag from a leguminous plant. Fenugreek leaves are available both fresh and dried. They have a bitter taste when raw, but when cooked they have a flavour that is slightly sweet and similar to that of celery. Fenugreek is high in protein, ascorbic acid, niacin and potassium.