A Chef’s Tips on Cooking Oils

October 2, 2020 by Juliet Bennett Rylah
Photo: Marco Verch/Flickr

Learning to cook or bake has been one of the most popular at-home activities since the pandemic left us at home with our own culinary acumen. One of the most basic components of cooking, whether it’s sautéing vegetables or frying up a chicken breast, is oil. Which should you use, and what do you use them all for? Here to answer these questions is Seamus Mullen, a chef with the Institute of Culinary Education in Pasadena. 

WLA: Which oils should I always have in my pantry and why? What is the best use for each?


SM: Honestly, I am a firm believer in extra virgin olive oil for EVERYTHING! The notion that you can only use it for low-temperature cooking and vinaigrettes is just not true. The smoke point for EVOO is 414 degrees Fahrenheit, so unless you’re doing a lot of deep-frying at very high temperature (most recipes deep fry at 400F), EVOO is the way to go. Even if you do go above the smoke point, you lose some of the antioxidants, but it’s still a better choice that an unhealthy oil like canola or “vegetable” oil. I’ve been cooking with EVOO my whole career and I spent much of my career in Spain where olive oil is king. I believe that the best quality olive oil comes from Spain.

I suggest keeping two olive oils in your cupboard, both extra virgin—a workhorse all-around cooking oil—and a fruitier, delicate oil for finishing or for vinaigrettes.

I do love coconut oil as well and I use it in baking as well as in Southeast Asian-inspired dishes. When I sear steaks or grill meats and I want a neutral flavored oil, I tend to use avocado oil. And for finishing delicate fish dishes, I love the aromatic flavors of walnut and pistachio oils.

WLA: What are some less common oils I might consider and what are the best uses for those?

SM: Argan oil is a nice, delicate oil for finishing. Mustard seed oil is super spicy and very common in Indian cuisine. Algae oil is a newer product that is quite neutral and seems to be gaining a lot of traction lately.

WLA: What are some of the biggest mistakes you think people make when cooking/baking with oil?

SM: Number one is thinking that the flavor and quality of the oil don’t matter. The reality is that, specifically with olive oil, the majority of the oil that is readily available is rancid, old, and often not even extra virgin. Olive oil is not just a cooking fat, it’s an actual ingredient and it’s important to use the best quality oil you can afford.

WLA: Good olive oil can be pricy. Any tips for an affordable, quality olive oil?

I would say that California Olive Ranch is a pretty good affordable buy. But as a general rule of thumb, whenever possible, purchase olive oil that provides the place of origin and the date it was produced.

WLA: What should I do with this rosemary oil I have? 

SM: That’s really nice for drizzling on fresh grilled lamb, right after you finish carving it. Rosemary is also really nice folded into a cold bean salad or even inside a grilled cheese sandwich.

Got any great tips for frying without any type of fryer, just a pan/skillet?

I like to use a heavy-duty Dutch oven. I always have a candy thermometer to check the temperature and I put a cast iron trivet between the flame and the Dutch oven to help maintain the heat. When heating the oil, heat it up gently over medium heat, then once it reaches temperature, reduce the flame to maintain the desired temperature. I always fry in EVOO from Spain and after I finish frying, I let the oil cool down completely, filter it through a coffee filter to remove any little bits, and then store it in a mason jar in a dark place. I can generally use the same frying oil 3-5 times before the oil is totally denatured.

WLA: How do I know if an oil has gone bad?

SM: Most oils shouldn’t be kept for more than a year past pressing date. Industrial oils like canola etc. last forever. However, that’s a pretty good indication that you don’t want to keep them hanging around! Olive oil will start to go rancid after a year, and you can tell by the unpleasant smell and taste.