Nuts in General are Kosher
Nuts fall under the category of foods grown from the ground and are therefore kosher in their raw form. Meaning, if one were in a field and sees almonds growing on a tree, theoretically, he or she could pick a handful of almonds and consume them without a problem (after, of course, discarding the shell). This rule applies to all fruits, vegetables, grains, and legumes. So long as they are raw, they are kosher, and unlike animals, fish, and fowl, there are no signs one must look for, such as scales or split hooves.
Nuts by themselves are considered pareve, meaning that they are neither dairy nor meat and can, therefore, be eaten with both types of foods. The blessing for most is borei pri haitz, which is the blessing said on food that grows on trees. The one exception to this is peanuts, which grow from the ground. Therefore, the blessing said on peanuts is borei pri ha’adama. Additionally, as long as the nut in question is raw and in its shell or its processed but has a kosher for Passover certification, it is 100% fine to eat on Passover.
Keeping Nuts Kosher
While in their raw form they are fine, things get murky the moment other ingredients are added or the nut is processed. This is why it is important to look for kosher certification on canned, bagged and flavored varieties. Even if packaged by themselves, one should check for certification if preservatives or oils were applied during processing or roasting. The same goes for nuts that are seasoned. Though they might be the only food in a can, if flavorings have been added certification is required. Additionally, if the nuts come together with other foods, say they’re mixed with chocolate and pretzels, you’ll need to verify that those other foods are kosher as well. If they’re not, then the nuts will not be considered okay for consumption, even if you pick them out and separate them from the other foods.
Finally, if a nut has been ground down or crushed, as in the case of almond flour, one needs to check for certification as well to be sure nothing has been added in the process that would make it not kosher. The same applies to ones that have been made into butters, such as peanut butter and cashew butter.
At Adam Seeds we have a mix of processed and unprocessed nuts and seeds. For this reason, we have made sure that our nuts and seeds are all under Mehadrin certification so there is no confusion.