The term ‘kosher’ refers to foods that are permissible under Jewish dietary law, or kashrut, as outlined in the Torah. Some foods are forbidden altogether (trief), while others may have forbidden parts that must be discarded, and there are also rules concerning preparation, manufacture, and which foods can be together. Any foodstuff that adheres to all of these rules is considered kosher, and may be awarded kosher certification to indicate that it has met the required standards.
One of the things forbidden under kashrut is the consumption of blood. This means that kosher meat must, among other requirements, have all of the blood removed, and one way of achieving this is to use large, coarse grains of salt to draw it out.
As well as being used for religious reasons, many people find that they prefer using these larger-grained salts for cooking and seasoning in general. Larger grains of salt spread their flavour over a larger part of the tongue and take longer to dissolve, resulting in a stronger flavour that lasts for longer. Kosher salt is also more tactile than finely-ground salts, which makes it easier to season food by hand.
Perhaps surprisingly, not all kosher salt is kosher certified. It takes its name primarily from the size of its crystals, which need to be large enough to use in the meat koshering process. Any salt with crystals of the right size can be referred to as kosher salt, not because it has been certified itself, but because it could be used to make meat kosher.
Because crystal size is what defines kosher salt, the method used to extract it is less important. It can be mined from salt deposits in the ground, or extracted from evaporated sea water. This means that some kosher salt is also sea salt. However, as sea salt tends to be more expensive, many people opt to buy mined kosher salt.
Benefits of kosher salt
Kosher salt is nutritionally almost identical to other types of salt, and while there may be small differences, you would have to far exceed the recommended daily intake of salt for it to have any impact. Salt in general is a necessary part of the human diet, and is essential for balancing fluids in the blood, as well as nerve and muscle function. However, the typical western diet includes far more salt than is necessary, which can lead to an increased risk of high blood pressure, heart attack and strokes.
It is sometimes claimed that kosher salt is lower in sodium than other salts, making it better for your heart. This is not true, however, with such claims being based on measuring by volume. Because of their irregular size, kosher salt crystals don’t fit together neatly like table salt does, which means there will be less actual salt in a teaspoon of kosher salt, and so, technically, less sodium. Gram for gram, however, they are the same.
When and how to use kosher salt
Kosher salt can be used for a variety of purposes. Using larger flakes makes it easier to distribute salt evenly when seasoning food, making it perfect for adding flavour to dishes both before and after cooking, as well as for seasoning water before cooking pasta or boiling vegetables.
It is also the salt of choice for pickling and brining. Table salt contains anti-caking agents that can turn the water an unappealing colour, but kosher salt is additive-free, and will dissolve without leaving any residue. It even has aesthetic appeal, with those large crystals adding extra impact to the salted rim of a margarita glass.
The only thing kosher salt is not really suitable for is baking, as larger salt crystals won’t dissolve into your dough or batter as easily. Here, you should turn to old-fashioned table salt, whose tiny crystals will melt into the mixture immediately.
Can I substitute sea salt for kosher salt?
As we have already mentioned, some kosher salt may also be sea salt, as long as the crystals are the right size. Sea salt has a more delicate texture than mined salt, and will also have a slightly different flavour due to trace elements from the sea water. In hot dishes, these differences will likely be lost during cooking, and while there may be a slight variation in flavour when used as a finishing salt, this will only be very subtle. Mined kosher salt can be used interchangeably with both kosher and smaller-grained non-kosher sea salt for everyday meal preparation, although obviously non-kosher sea salt is not suitable for koshering meat.
Conversion of kosher vs sea/table salt
When substituting kosher salt for table salt or a smaller-grained sea salt, it is important to remember that there is actually less salt in a spoonful of kosher salt than there is in a spoonful of table salt. This is because the larger, coarser kosher grains don’t fit together snugly, and so there will be gaps between them. Because of this, you need to use slightly larger measurements for kosher salt, although the difference will be negligible for very small amounts. Use the following conversions as a guide, and you shouldn’t go far wrong.
For every ¼ tsp table salt, use ¼ tsp kosher salt
For every 1 tsp table salt, use 1 ¼ tsp kosher salt
For every 1 tbsp table salt, use 1 tbsp + ¾ tsp kosher salt
Certification for kosher salt
Most of the salt we refer to as kosher salt is not actually certified. Some salt, however, is certified as kosher, and this guarantees that the manufacture and packaging has been observed, and that none of the ingredients or processes used are contrary to kashrut dietary law.