Cooking oil is such an important and essential ingredient in our day to day cooking. Whether it be salads, fries, curries or grilling and baking, oil is used in varying proportions and therefore it begs the question, what if we upgrade it? In India, when you're starting the dish, oil or fat is heated in a cookware first, before adding herbs or whole and ground spices. This is because the heat of the oil makes the spices release their flavour into it, which then flavours the rest of the ingredients of the dish. Not only do infused oils add an extra dimension to your cooking, it fortifies the oil making it healthier, flavourful, aromatic and nutritious. They're versatile and add flavour to many day-to-day dishes. It is always recommended to choose oils that do not have a strong aroma or flavour of their own, and that provides a neutral base for our herbs and spices to work their magic on. Aromatic oils like olive and mustard oils can also be infused, but take care of the fact that the infusion shouldn’t overpower the original smell and flavour of the oil, rather accentuate it. Now, there are two ways to infuse cooking oils.
Cold Infusion
Herbs and spices can be infused in oils without heating them up in any capacity. Simply preparing infused oils in small batches and refrigerating them does the trick. Do not introduce water or fresh herbs into the oils, as they'll bring moisture and bacteria to the mix, rendering it inedible in a few days. Use dried herbs like rosemary, thyme, bay leaf, curry leaves, oregano, chilli flakes, parsley and basil to infuse with the oil over time as it slowly releases its flavours into the oil, by means of having it submerged under the oil in the storage container.
Heated Infusion
A cup of oil is mixed with 4 to 5 tablespoons of spices and herbs and brought upto a high temperature in the stovetop. The oil being heated would allow the spices to release their flavours into the oil and therefore get infused instantly. You can add crushed garlic and fresh herbs to the oil if you're looking to do so, because in this process, water or moisture will evaporate from the contents, and the high temperature would warrant the growth of any bacteria.
After the heated infusion process, one must let the oil come down to room temperature on its own. The longer you let the ingredients sit in the oil, the more flavourful the oil will be. Check for how successfully you've managed to infuse the spices and if you're dissatisfied, put it back on heat and add the necessary ingredients to enhance or balance out the flavours. Strain the oil into food-grade glass containers, not plastic containers, as the inner surface of the plastic container will interact with the oil, thereby ruining it.