You Don't Refrigerate Vinegar or Olive Oil, So Do You Need to Refrigerate Vinaigrette? (2024)

A bright, zingy vinaigrette makes a delicious addition to salads, roasted vegetables and so much more, and they're fairly quick and simple to whip up. But if you're making it ahead of time or have leftovers, how should you store it? Olive oil and vinegar, the two main ingredients, don't need to be refrigerated. Plus oil solidifies in the fridge, and no one wants a chunky vinaigrette. So does it need to be refrigerated? We chatted with two experts to get to the bottom of this culinary conundrum.

Why Don't We Refrigerate Oil and Vinegar?

Oli and vinegar are two products that can be safely stored at room temperature. Tamika Sims, Ph.D., senior director of food technology communications at the International Food Information Council, explains that the acidic nature of commercially produced vinegar "prevents the growth of microbes inside of it that can yield foodborne illness." As a result of this, she notes that vinegar has "an almost indefinite shelf life." She explains that while some kinds of vinegar, like red-wine vinegar or balsamic vinegar, may change color if kept for extended periods of time, even if they're past their "best buy" date they are unlikely to be spoiled. "A 'best if used by' or 'best if used before' date indicates when a product will be of the best flavor or quality. It is not a purchase or safety date," she says. Homemade vinegar, on the other hand, may not be at the same level of acidity as store-bought, and there's a chance for harmful bacteria to grow inside it. "It may be best to store homemade vinegar in the refrigerator and monitor any signs of spoilage such as cloudiness or an off smell," Sims says.

Unlike vinegar, cooking oils cannot be stored indefinitely. "Light, heat and oxygen can all cause oil to go rancid over time," says Ann Ziata, a chef at the Institute of Culinary Education. Because of this, she recommends storing oils (especially extra-virgin and unrefined oils) in an airtight container away from light and heat. Sims adds that if you have an oil that has changed in smell, color or texture, it's time to throw it away because, unlike vinegar, "oils can support the growth of potentially harmful bacteria" and their palatability and nutritional quality can decrease over time. Definitely pay attention to those "best by" dates for olive oil, and consider buying it in smaller quantities that you know you'll use up within a few months.

So Then Does Homemade Vinaigrette Need to Be Refrigerated?

In general, it's a good idea to refrigerate homemade vinaigrettes. The exception to this would be if your homemade vinaigrette solely consists of shelf-stable ingredients like oil, vinegar, salt and pepper. "Even with some mustard, honey or tahini included, the vinaigrette will likely be safe to eat unrefrigerated; however, the flavors will keep best when stored cold," Ziata says. "Refrigerating vinaigrettes is a good habit to have, especially if various other ingredients are being added in for flavor and/or emulsification." She notes that you should always refrigerate vinaigrettes that include perishable ingredients like eggs, heavy cream, citrus juice, fresh herbs and vegetables.

Sims notes that unless your vinaigrette is a mixture of just oil and vinegar, refrigeration is your best bet from a food-safety standpoint. "If you add in vegetables and/or herbs, the potential growth for Clostridium botulinum becomes a factor," she said. "Botulinum spores can be quite harmful and are a serious foodborne illness matter, and many illness outbreaks over decades have been traced to home-prepared vinaigrettes and vegetables in oil." The best way to prevent these spores from growing is refrigeration.

When you take your homemade vinaigrette out of the fridge, you may find that the mixture has separated. "If the vinaigrette loses its emulsion in the fridge, and the oil solidifies and floats to the top, bring it to room temperature about 30 minutes before serving, and whisk [or shake] to bring the emulsion back," Ziata says.

Does Store-Bought Vinaigrette Need to Be Refrigerated?

While store-bought vinaigrettes may contain stabilizers and preservatives to extend their shelf life, it's a good idea to refrigerate them after opening. Ziata notes that doing this will help the dressing last longer and taste better. Sims recommends following the instructions on the product label. "These instructions can save you from botulism exposure and prevent serious illness," she says.

When Stored Properly, How Long Do Vinaigrettes Last?

Homemade vinaigrettes that include fresh or cooked vegetables (like garlic), herbs and fresh citrus juices will last around three days, according to Ziata. Preservative-free vinaigrettes you'll typically find in the refrigerated section of the grocery store will last a little longer, three to five days. "Inexpensive, shelf-stable bottled dressings will last a month in the fridge, if not longer, thanks to their preservatives," she says.

Sims added that store-bought vinaigrettes generally last longer "because food processors have access to processing techniques and ingredients that many of us will not have at home that prevent microbial growth and spoilage."

Bottom Line

While oils and vinegars don't need to be refrigerated on their own, once you add in ingredients like fresh-squeezed citrus juice, mustard and garlic to make a homemade vinaigrette, it's a good idea to pop any leftovers in the refrigerator. Doing so will help your homemade (and store-bought) vinaigrettes last longer and hold onto peak flavors, and help keep you safe from foodborne illnesses. If you find that your vinaigrette has solidified and/or separated after storing it in the fridge, give it time to come back to room temperature before whisking it up to emulsify the mixture once again.