I've made many many things from scratch, from macarons and Worcestershire sauce to wedding cakes and plum liqueur. The long process is something I enjoy, and the end result is usually pretty good. However, in terms of cost performance, making things from scratch doesn't save you much money. Like hand-knit scarves, it actually costs more to make some things on your own than to just buy it at the store. Macarons might be cheaper to make at home, but the success rate isn't 100% so it's not so bad to just pay $2 for the tiny thing.
Mustard, on the other hand, is something definitely better to make at home, both for cost and taste. Plus, it is almost impossible to fail. Furthermore, you can add whatever you would like (within reasons) to create your own favorite mustard. I will show you how I made mustard based on many "spicy Guinness mustard" recipes available. Again, you can add whatever you like to create your own favorite homemade mustard.
This is a fool-proof process.
15oz can of Guinness
1 1/2 cup of mustard seed
6 tbsp mustard powder
1/2 cup of red wine vinegar
1/2 cup of rice vinegar
1 tbsp salt
1 tsp pepper
1/4 tsp each of cinnamon, clove, nutmeg and allspice
As you can see, mustards seed are VERY cheap. If you buy them at the regular grocery store's spice isle, it can be pricey. But I found this big tub for only $1.99 at Manhattan Fruit Exchange in Chelsea Market!
Mix everything together. Leave it on kitchen counter for 2 days so that mustard seeds can soak up all the liquid.
At first, the seeds are tough, like this:
After soaking in the liquid for two days though, the seeds will plump up:
Time to blend everything together. Using an immersion blender will be the easiest (or you can use regular food processor):
Mix until the texture becomes smooth. Depending on how you like your mustard, you can keep everything going until it's very smooth, or barely mix together for a more coarse texture.
I stopped mixing somewhere in the middle of smooth and coarse.
If you buy a box of canning jars, it usually comes with this nifty funnel that fits perfectly on top of the jars:
This makes about eight 125ml jars of mustard. I made double the batch, and ended up with 12 small jars and 1 large jar.
You can create a nice sticker to put on top of these jars and it will make a very nice gift.
Homemade mustard is very pungent in the beginning. As time passes, the flavor will mellow down. You can't compare this with the store-bought kind, that's for sure. This is probably one of the easiest recipes, and worth it as long as you can find a cheap source for mustard seeds.