There are a lot of fancy kitchen toys out there -- some of which are more useful than others -- but there are some things that can't be improved upon even with the latest technology. The mortar and pestle is one of those things, and your kitchen needs one.
You could maybe argue that it isn't a "necessity", but "need" is a funny thing. Do you need your food to be the most flavorful version of itself it can be? I mean, I guess not, but you probably want it to be. You could mince and mash garlic, ginger and fresh herbs into a flavorful paste, perfect for spreading on chicken or stirring into a stir-fry, but there will be chunks, and you could get there much more quickly by pummelling them with a pestle. You'll also get a smoother, more flavorful paste this way, as crushing those cellular walls is going to release tasty goodness more efficiently than cutting them would.
Why not use a food processor? Or a spice grinder? Again, we're dealing with with cutting versus blunt force trauma but, as a chef friend of mine pointed out, those appliances have motors, and motors generate heat, and heat can degrade and mute bright, bold flavours. There's also a matter of scale. If a recipe calls for a single tablespoon of freshly ground, toasted cumin seeds, trying to grind those with even the smallest of food processors is going to be a frustrating and most likely futile effort. Beyond grinding fresh spices and making flavorful pastes, this lo-fi, multi-functional kitchen tool can be used to whip up any of the following:
- Guacamole: You'll need a big one, but it's very impressive.
- Chimichurri: Perfect for barbecue season.
- Curry paste: Yes, you can buy curry paste in the store, but think how proud you'll be of your super flavorful creation.
- Pesto: Channel your Italian grandmother, be she real or imagined.
- Caesar dressing: Garlic and anchovies emulsify much better as a smooth paste.
- Flavoured salts: Because nothing else with get those flavorful bits fine enough.
Mortar and pestle sets come in a variety of materials, including wood, glass, granite and marble, but I find wood to be too porous, and glass to fragile. Marble (which is what I have) is pretty good, but a Thai granite mortar and pestle is the platonic ideal, with a smooth, hard surface that can take a beating and be wiped clean without stuff getting stuck in crevices or pores. You can find one online, but it's also worth checking out your local Asian market, if you are so lucky as to live near one.