Why is Diamond Crystal most usually recommended for kosher salt?

Question

In a number of recipes, I see Diamond Crystal recommended as the kosher salt to use.

Where I live, only Morton's is available.

Is there some superior quality to Diamond Crystal kosher salt that I might not get out of another brand?

Answer 1

Many recipes specify salt measurements by volume, but different brands of salt vary by density. In order to consistently predict the weight of salt used, recipe authors fix the density by fixing the brand.

If you want to know whether you can use the brand that's available to you, the answer is yes. You just need to convert the units to weight.

From Simply Recipes:

By weight, the brands are the same and can be used interchangeably. This is why you should ideally always measure large amounts of kosher salt by weight to be precise.

But if you’re measuring by volume — or if a recipe only lists the kosher salt by volume — you can run into issues. Since Morton kosher salt is has a finer grind, you’ll pack more into a cup than if you’re using Diamond Crystal. This can really throw off a recipe!

First off, look for (or ask!) which brand of kosher salt is recommended in the recipe, especially if the recipe calls for larger amounts of salt. (If you only need a teaspoon or so, you're usually ok using either brand without throwing off the recipe that much.)

Then either use the brand specified, or follow this conversion chart:

• 1 cup of Morton’s Kosher Salt = 241 grams = 1 3/4 cup minus 1 teaspoon of Diamond Crystal Kosher Salt

• 1 cup of Diamond Crystal Kosher Salt = 137 grams = 1/2 cup plus 2 teaspoons of Morton’s Kosher Salt

137/241 is approximately 0.568, or a bit more than half. If you need to be precise, measure by weight.

Answer 2

Superior quality is obviously a matter of opinion, and it is the opinion of several influential chefs that Diamond Crystal is superior. The main thing they like about it is that Diamond Crystal is formed by evaporation instead of Morton's mechanical action, making it lighter and more delicate.

For example, Samin Nosrat, author of Salt Fat Acid Heat had this to say:

Nosrat also notes that Diamond Crystal dissolves much more quickly than Morton. “The more quickly salt dissolves, the less likely you are to overseason a dish, thinking it needs more salt when actually the salt just needs more time to dissolve.”

Other chefs feel the same way about Diamond Crystal, also noting that because its structure makes it less dense, they are less likely to oversalt things.

You'll notice that all of the quotes are related to using Diamond Crystal as a general-purpose cooking salt. Clearly, these superior qualities do not apply when measuring it for baking or using it for its original purpose -- kashering meat. In fact, for the latter purpose, it's possible that Morton's is superior as the denser crystals do more to draw out fluids before dissolving. For the same reason, one might hypothesize that Morton's would be better for BBQ rubs and similar applications (sadly, though, no data here; Diamond's trendiness is strong enough that Morton champions aren't publishing).

Answer 3

Pro cooks will always go kosher over table salt...easier to dose more consistently...and, Diamond is just found more in pro kitchens, so cooks are used to it. It is simply a matter of growing comfortable with the dosing and then being consistent. Salt is salt, brand matters little in that regard. However, Diamond crystals are slightly different from say, Morton crystals. If you use a lot of one brand, you get comfortable with how it behaves and therefore it gets "recommended."

Answer 4

I've used Diamond Crystal in my home kitchen for over a decade now. I recently was doing an extended stay out of town and could only find Morton kosher salt. Aside from the density differences that people have pointed out, the big difference I found was that Diamond Crystal comes in thin flakes (but not as flaky as, say, Maldon salt), whereas Morton is fairly coarse grains, like coarse sand or very small pebbles. When I went to salt meat or other "wet" food, most of the Morton salt bounced off instead of sticking like Diamond Crystal, which has a higher surface area-to-volume ratio.

Answer 5

After even more confusion, let's bring this down to a straight answer to the exact question, as asked…

"Is there some superior quality.."
No. Salt is salt.

It seems people in comments below have been so preoccupied with whether or not we have kosher salt in the UK or EU - we don't - that they've forgotten the entire point of this answer…
There is no "best salt".
All salt tastes the same by the time it's mixed in with your food^[1]. Use it by weight not volume if you ever change your crystal size.
[1] this may not be true for iodised salt, but I don't think I've ever tasted it. It's not unobtainable here, but is very much a tiny slot on the salt shelf in a supermarket.

From comments again - apparently iodised salt has a metallic overtone.
I also just discovered why the UK doesn't need iodised salt - they 'fixed' the milk instead - https://www.bda.uk.com/resource/iodine-deficiency-in-the-uk-dietetic-implications.html

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Pro cooks in the UK have been using table or cooking salt for far longer than we've had cooking shows or internet recipes. Until the invention of the interwebz we'd never heard of kosher salt. [This turns out to be because it's a US naming convention to indicate 'purity', apparently because most other US salt is iodised.]

Salt is salt, give or take the odd anti-caking agent.
The only difference in salt "types" is the volume/weight ratio… & price.

UK prices…
Table/cooking salt — £1 per kilo
Kosher salt [imported] — £7 - 15 per kilo
Himalayan salt [another outrageous money spinner that can only be qualified as "they saw you coming & laughed"] — £33 per kilo.
They all taste exactly the same.

You get used to the quantities you need in a recipe by experience. If you read an international online recipe, then whatever value it gives for added salt, use your prior experience - unless one or more of the ingredients is particularly salty, it will be the same quantity as you always use.
If it says use kosher salt & you only have table, then don't measure in spoons, measure by weight, or drop the usage by 2/3… or, as many recipes say - "season to taste"… a bit to start with, check it part-way through, make sure it's right at the end.

There is no such thing as a "best salt".
Don't believe the hype.