Sesame seeds are used in Japanese cooking quite often in various forms – as oil, as paste, whole and ground., and they can be used as sauce, seasoning, and condiments in both savory meals and desserts. There are mainly three types of sesame seeds available in Japan; white, black and gold, but white and black are more commonly used. Sesame seeds can be unhulled or hulled and roasted or unroasted. And the variations in seed and processing yield very different colors and flavors. The black ones tend to be remain unhulled because the skin has the color (the inside is white.) Both the white and black seeds are used in any forms, but the higher oil content and lower cost of the white seeds make them preferable for most common uses, while the unique color make the black ones preferable for garnishes or a special occasion. The sesame seed skin has extra nutrition and extra flavor, but it can be hard to digest and sometimes the skins stay in your mouth; so, some people prefer hulled ones especially when is the seeds are used whole. Sesame seeds in general can be hard to digest; so, oftentimes they are ground into a powder or paste.
Below are the typical forms of sesame seeds in Japan and instructions for how to easily prepare some of them at home. It is always good to roast sesame seeds right before preparing any forms at home even they have already roasted. Just re-roast them quickly, and that will always help to yield extra flavor and aroma.
<Different forms of Goma (sesame seeds)>
Arai goma: washed goma
Migaki goma (Kawamuki goma): hulled goma
Iri goma: roasted goma
Suri goma (Atari goma) : ground and roasted goma
Kiri goma: chopped goma
Hineri goma: twisted goma
Neri goma: sesame paste. Similar to tahini. Most people think the difference is that neri goma is made with unhulled sesame seeds and tahini is made with hulled sesame seeds, but neri goma can be made from both unhulled and hulled one. I think the difference is in length of roasting time. Even tahini with roasted sesame seeds is not roasted as much as neri goma. So neri goma has a nuttier flavor in general. Chinese sesame paste contains sesame oil, and sometimes other ingredients such as garlic have been added. So tahini can be a substitute for neri goma, but Chinese sesame paste generally cannot be.
Goma abura : sesame oil typically toasted, but untoasted one is also available
<Preparation Methods for different forms>
Iri goma (roasted sesame seeds)
Stove: Heat a small clean pan (without any oil) over medium low heat, and pour sesame seeds to make a single layer. Toast until they have reached a golden brown for about 10 minutes. Shake the pan or stir with a wooden spoon often. Remove the seeds from the pan (otherwise it will keep cooking), and let it cool before putting them in a container.
*Hulled sesame seeds cook quicker than unhulled ones.
*If you are re-roasting sesame seeds that are already roasted, it will only take a few minutes.
Oven: Pre heat an oven to 300 degree. Spread the seeds out on a baking sheet, and bake until fragrant and golden brown for about 15 minutes. Shake the pan or stir with a wooden spoon a few times. Remove the seeds from the pan, and let them cool before putting them in a container.
Suri goma (grounded roasted sesame seeds)
Make iri goma (above recipe) first if the sesame seeds are not already roasted, but I recommend roasting it even if it is roasted for better aroma and flavor and for better handling. Put the roasted sesame seeds in a Japanese mortar and pestle (suribachi and surikogi) while they are still hot, and grind them. Sesame seeds are normally ground into three different roughnesses depending on dishes you are preparing. Arazuri (grounded roughly) still contains visible sesame skins. Hanzuri (half or 50% grounded) still has roughness compared to fine powder. Shichibuzuri (70 % grounded) is almost fine powder. A Japanese mortar and pestle works the best here since the rough grooved surface help to bring out the oils in sesame seeds, but a small food processor or a food mill can also be used.
Use: garnish, sauce, dressing, soup and dessert
Kiri Goma (chopped sesame seeds)
Place iri goma on a cutting board, and chop them for better aroma.
Hineri goma (twisted sesame seeds)
Smush iri goma between two fingers for better aroma.
Neri goma (sesame paste)
Traditionally one just grinds toasted sesame seeds with a Japanese mortar and pestle until paste forms, but this takes a long time. Instead, you can use a small food processor, a food mill, or a coffee grinder. Pulse until is the seeds are ground finely and its oil has come out, scraping down the sides of the container as needed. Add a few drops of sesame oil (I prefer an unroasted one), and continue the process until it mixes well. Some people move the mixture into a Japanese mortar and pestle at this point to make smoother paste, but this is not necessary.
Use: sauce, dressing, soup and dessert