Is it advisable to cook cilantro or mint leaves and store them, instead of blanching them?

Question

The problem:
The grocer only agrees to give a large bunch of cilantro (coriander) or mint leaves, and I need it to last a month or more, because I don't use the herbs as frequently.

What I've tried earlier:

• I've poured some water into the plastic bags containing the cilantro or mint, so that their roots (and leaves) were wet, and this was stored in the fridge. (turns out, wet leaves tend to rot faster)

• I've blanched cilantro leaves, placed it in a plastic zip-lock bag and kept it in the freezer. When I took it out and let it thaw, it looked like greenish yellow seaweed, and a good amount of water had collected in the plastic bag. The cilantro didn't smell too good either.

What I'm asking about:
I want to know if it's advisable to chop up fresh cilantro or mint leaves, boil some water or oil in a thick-bottomed container, and simmer the chopped cilantro or mint in it until it gets fully cooked. Then I could store it in the fridge or chill-tray (or if it's cooked in oil, I guess I could store it in the freezer). I'm hoping this would make it last longer and preserve the flavors too. One thing I'm worried about is, whether cooking it in this manner will make the cilantro taste bitter. When making mixed vegetables curry or chicken curry, whenever I've added cilantro before adding the chicken or vegetables, the curry ended up having a slightly bitter taste.

ps: From this answer, I see I can store them in the freezer without blanching (but it needs to be kept within a paper towel). It is said to mess with the texture though.

Answer 1

No, it is certainly not advisable.

Cooking reduces the fridge life of plants. If you cook your herbs, they will only last 3 days in the fridge. Besides, you will also change the taste, and not for better.

The advice you found on freezing is indeed the only way to keep herbs for a month. They do indeed look unappetizing when thawed, but you are supposed to use them in soups and other hot dishes, where the change in texture won't be noticeable. You should just throw them in without thawing, it is not only less work, but all that juice leaking out will go into the dish, instead of getting thrown out with the bag.

If this does not work for you, the only other methods are to either switch to cooking with dried herbs (much more convenient, but very different taste) or to grow you own. But you cannot preserve the picked herbs in their fresh state by any method.

Answer 2

If you want a "fresh herbs" taste, then freezing herbs without first cooking them is the way to go. Cooking herbs longer won't make them taste any fresher than blanching them did.

In my local grocery stores and supermarkets, they sell "frozen herb cubes", something like These cubes from Dorot, although they are made by other brands as well. They taste pretty good when defrosted, and last a while. The ones you can buy in the store are made with minced herbs, water, oil, and a bit of acid and salt (I'm guessing to maintain color, but I don't really know for sure).

However, a bit of googling for "frozen herb cubes" showed all kinds of methods for freezing fresh herbs mixed with water or olive oil, which can then be defrosted (or just put into food while frozen) and used for various purposes with only a little bit of decreased taste. For example, these instructions from America's Test Kitchen seem pretty reasonable.

I have never tried freezing herbs myself, but most of the articles and instructions I found say that it works very well and the frozen herbs taste more fresh than dried herbs. I also have seen some reservations about freezing delicate herbs like basil, but many of the store-bought brands do have basil available (and it tastes fine), so it might just require a bit more tweaking and care.

Answer 3

I actually think you can keep most herbs in the fridge for a month.

For cilantro or parsley, treat them like a bouquet of flowers. Put them upright in a jar with water so just the stems are submerged, then loosely tent a plastic produce bag over top.

For herbs that don't have long enough stems for that method, try moistening a paper towel so it's damp but not dripping, fold the paper towel around the herbs, and placing in a sealed plastic bag.

If you're intent on longer term storage, I agree that freezing them uncooked is the way to go.

Answer 4

The best treatise on how to store fresh herbs (particularly more tender ones like cilantro, parsley, mint as opposed to say, rosemary, which I would just freeze) I read comes from Kenji López-Alt over at seriouseats.

It boils down to two main techniques:

(0. wash the herbs and spin them in a salad spinner or pat them dry)

1. store more hardy herbs in a damp paper towel, and wrap that in plastic wrap or a ziplock bag
2. store more tender ones like parsley by snipping the stalks, remove any already wilted leaves, and store them upright in a mason jar with a bit of water in the bottom and a lid or plastic wrap over the top of the mason jar.

I have used slightly more lazy variations on this (as I usually go through a small bunch of herbs pretty quickly) with great success, particularly for cilantro.