Have you ever noticed an odd, gray-looking foam appearing on top of your lentils when you let them soak for a while, or sometimes even when you rinse them? Sometimes, this also appears when you cook them, and it can be unappetizing and even alarming.
This foam forms because the lentils contain something called saponins. When saponins are combined with water, they create a lather, like the lather you get from soap. Soap is created from saponins, and they are found in many kinds of foods, so this is nothing you need to worry about. It’s perfectly normal and it won’t hurt you at all.
In this article, we’re going to find out more about why lentils create foam when they are washed or cooked. We’ll also explore saponins, why plants produce them, and whether you need to be wary of them!
What Makes Lentils Foam?
On the simplest level, lentils foam when they are combined with water, for the same reason that soap foams when you combine it with water. A little moisture and a little agitation are all that is needed to produce these white or gray bubbles. You don’t need to be concerned if you see this, even if it looks alarming.
Lentils may foam if:
- You leave them to soak
- You rinse them thoroughly in running water
- You boil them
This can happen with other foods too, but it’s often most noticeable with lentils and other similar foods. It’s simply a result of the saponins being released and interacting with the water.
Remember that saponins are in many kinds of foods, including things like grapes, so you probably eat them almost daily.
Why Do Lentils Contain Saponins?
Lentils contain saponins because plants developed these as a natural defensive mechanism. Saponins taste bitter and unpleasant to birds, mammals, and insects, and that means the plants are less likely to be eaten.
However, saponins can actually be pretty healthy, and it’s thought that they can lower your cholesterol and possibly even reduce your risk of cancer. Often, the saponins are mild enough once cooked (or in the parts of the plant that we eat) that they are not unpleasant, even if you might not want to eat the whole, uncooked plant.
Do You Need To Get Rid Of The Foam?
Some people choose to skim the foam off lentils while they are cooking them, or rinse them until the water runs clear. However, this foam is completely harmless and there’s no particular reason to remove it.
Although eating soap might give you stomach ache, the level of saponins in lentils is so low that they will not upset you at all. If you ate an enormous amount of lentils, you might get some effects from the saponins, but you’d have to eat extraordinary amounts before you’d need to worry about this.
It’s therefore not worth removing the foam, but you can do so if this makes you feel more comfortable. You can also reduce foaming while cooking by rinsing the lentils more thoroughly before you start cooking them. This may be easier than trying to skim the foam off the top of the pot.
If you do want to remove the foam, you can take a big spoon and simply slide it back and forth in the pan, at the surface of the water. The foam will collect on the spoon, along with some of the water, and you can then wash it down the sink. There’s no need to do anything else; this will be sufficient.
Can You Prevent Foaming?
If you dislike the appearance of the lentils when they start foaming, you can try adding a splash of oil to the pan while the lentils are cooking. This will form a barrier between the lentils and the water, and may reduce how much foam they produce.
This isn’t really necessary and a lot of people don’t bother to do it, but if you want to stop the foaming, it’s an option. However, if you don’t do it, your lentils will taste much the same and will be just as nutritious.
If you thoroughly rinse the lentils before you start cooking them, you should also find that they foam less while they are being boiled, because most of the saponins will already have been washed down the sink. Again, this is not necessary, but it can be a good option if you find the gray foam off-putting or you want to get rid of it for some other reason.
Conclusion
Your lentils will foam as the saponins contained within the lentil are released into the water and get agitated. This will cause them to lather up, forming a gray foam on the surface, just like lathering soap will cause foam. Saponins are harmless in these quantities and there’s no need to worry about washing them away.
