You can go straight to the spices Index if you don't want to read the intro :)
Indian spices and the way that you use them are what gives Indian food its character. Of course it started out as a necessity. In a hot climate, before refrigeration other ways were found to preserve food. Exactly how this was discovered by folks of older times is a not exactly known - trial and error I guess.
Of course not all the spices are originally native to India, chillis for example originated in Central and South America. I use the term Indian spices because they are widely used in Indian cooking and are now nearly all grown in India.
Still, it is clear that they have been a part of Indian cuisine since before recorded time - at least 7000 years ago. (See more in the history pages when I have written them).
And how many are used in Indian cooking? Well there are probably as many as 100 different ones but don't be alarmed, you can start with a few and this will do for a large number of recipes. And if you haven't got something a recipe calls for, then the resultant meal might be missing something, but omitting it probably won't ruin the dish - grow your collection and try it again when you have it.
Indian spices are made from virtually every part of various plants;
seeds, e.g. coriander, cumin
berries and other fruits, e.g. pepper, chilli, cardamom
root system, e.g. ginger, turmeric
flowers, e.g. cloves, saffron
bark. e.g. cinnamon, cassia
and even the sap! - asafetida
things deriving from the leaves of plants are usually called herbs but are often dried and used like spices.
In addition to this, these various plant parts can be treated in various ways to produce different results. Amchoor for example is an unripe mango, dried and ground to a powder. Black, white and green peppercorns all come from the same plant, just different processes.
Overall there must be 100s of spices - my own spice cupboard probably has about 30-40 (never counted).
Most dictionaries specifically refer to spices as being vegetable based (which rules out salt) and the word ultimately originates from the Latin 'species' (which pretty much implies something living).
Generally spices are any part of a plant that has been treated so as to preserve it, and which is added to food to change or improve the flavour, or to impart some other culinary benefit (e.g. as a preservative or a digestive aid).
It is a good idea to always buy your Indian spices whole, then you can and grind them yourself, they keep much longer that way. If stored properly, they keep for up to 2 years. Once ground, they will start to lose their essential oils quickly and should be thrown away after 6 months (they really won't taste of anything much by this time).
Store in airtight containers away from light and heat. (I have recruited an army of empty pickle and chutney jars for my collection). It's all about keeping the essential oils from evaporating so common sense things like don't store next to the cooker.
If you are a beginner wanting to get started on the spice trail, then there are a few good spice sets available. Here is a very nice one that contains all the basics and even has a ready made curry powder Organic Indian Spices Gift Box of Minis
Personally, I rarely buy ready made curry powder. Call this snobby or purist if you like, but I like to know what is going on. Besides which making your own is fun. Not only this, I rarely even make curry powder in quantity to keep - because what is even more fun is that every time can be slightly different.
Having said that, there is nothing particularly wrong with either shop bought curry powders (and there are an increasing number of really excellent ones now) or home made mixtures, particularly if you are a newbie or short of time. See my Curry Powder recipes for some ones that I have done.
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