A Toast to Sesame Oil

There are two types of sesame oil, and they can’t be used interchangeably. Plain sesame oil, which is pressed from raw sesame seeds, has almost no color, flavor, or scent. It also has a high smoke point, which makes it a good cooking oil. By contrast, toasted sesame oil is deep amber to brown in color, with an intensely toasty, nutty aroma and flavor and a much lower smoke point. We generally don’t cook with it but use it as a finishing oil, adding a teaspoon or two at the end of cooking or incorporating it into a dressing or sauce. 

Because it’s such an important element in so many of our recipes, we chose to focus on toasted sesame oils, and bought eight top-selling products, priced from about $0.40 to about $1.60 per ounce, to discover which tasted best. Twenty-one staffers at America’s Test Kitchen sampled them in two blind tastings, first plain and then in Rice Salad with Peas and Mushrooms.

We were surprised by how much the oils differed in taste. Tasters described flavors that ranged from “nutty, toasty, tasty,” and “a touch smoky,” with an “almost oaky or bourbon quality,” to “a bit too delicate” or, worse, “fishy” and “too intense.” To understand these flavor variances, it helps to know how toasted sesame oil is made. Before milling or pressing whole sesame seeds to extract oil, manufacturers roast them. The roasting step is key: Just as when nuts or coffee beans are roasted or bread is toasted, the application of heat kicks off the Maillard reaction, which creates new flavor compounds and turns the seeds deep golden brown. After the seeds cool, they’re pressed, and the new amber-colored oil is filtered to remove seed particles before being bottled for sale. No other treatment, additives, or enhancements are needed.

According to experts, including a 2016 article published in the International Journal of Food Properties, the biggest factors causing the different sensory qualities of toasted sesame oils are the seeds’ roasting times and the temperature at which they’re roasted. Just like when you toast a slice of white bread, depending on the heat setting and the length of the toasting time, the resulting color and flavor will range from unchanged and pale to golden and sweetly caramelized to black with a burnt taste. There’s brinkmanship involved in toasting sesame seeds, where higher, hotter temperatures and/or longer roasting times yield more than 240 volatile aroma and flavor compounds, with pyrazines, which provide roasted, nutty flavors, being one of the most prominent. But roasting increases the presence of compounds such as pyrazines only up to a point. When the roasting continues too long or at too high a temperature, other, less favorable flavors appear.

 While manufacturers keep their exact roasting times and temperatures a trade secret, it was easy for our tasters to perceive whether the seeds for these oils had been toasted too much, too little, or just enough, and the resulting flavors clearly influenced our rankings. One oil had a pale color and “delicate” toasted flavor that some tasters found delicious when plain but too subtle when we mixed it into rice salad. Another was fairly fierce, with bitter, burnt notes when tasted plain, but the unfavorable impressions disappeared when we used it to dress the rice salad, leaving behind the intense roasted nuttiness and just a hint of char. But the lowest-ranked oils had stronger off-flavors that persisted in the rice salad, leaving acrid, bitter impressions with our tasters. Because we add toasted sesame oil specifically for its flavor, whether it’s in a simple dressing or dipping sauce or in another application where it is not cooked, we preferred oils that tasted great both plain and in a recipe.

While we recommend most of the oils we tasted, our favorite was Ottogi Premium Roasted Sesame Oil. It won over our tasters with its well-developed rich, deep toasted sesame flavor and aroma that reminded some of peanut butter or tahini while avoiding the bitter, acrid notes of less-favored oils. Tasters gave it high marks when they tasted it plain, and they also enjoyed the way it added depth and complexity to the rice salad. It is also one of only two oils in our lineup sold in dark-colored, nonreactive bottles that protect the oil quality, and tasters appreciated the resulting fresher flavor. One final note: We’ve learned that Ottogi is sold in two different containers that are made in two different countries. The glass-bottled version, which we tasted and recommend, is made in China. The version sold in metal tins is made in South Korea and has less nuttiness and more charcoal notes; we prefer the glass-bottled oil. We’ll be stocking it in our pantry.