If you’re in a hurry and need to make a salad, a ready-to-use dressing comes in handy. And almost everyone has a collection of half-open bottles scattered around the fridge. But does salad dressing go bad?

If you don’t necessarily want to eat ranch or Italian dressing every night of the week, you don’t have to. Store-bought salad dressings often have a long enough shelf life that you finish the bottle. And if you have bought many bottles, the unopened ones will keep for years.

In short, if you have any questions or concerns about salad dressing storage, expiration, and spoilage, this article is for you.

How to store salad dressing

Store-bought salad dressings come in two forms.

The simplest is the dry mix, which normally only requires water and/or oil to prepare the dressing.

Another way is ready-to-use dressings, convenient to keep on hand and ready to use when you need them.

Most ready-to-use dressings are sold unrefrigerated, but you can sometimes find ones that are stored in the refrigerated area. The latter usually have fewer preservatives, or even lack them, so they need to be kept at a low temperature.

Let’s start with the dry mixes. They do not require much storage. You just have to make sure that the package is in a cool and dry place. If you’re like me, you keep them in the spice drawer.

If you open the package and don’t use it all at once, close it tightly if possible. That keeps moisture and air circulation at bay, so the mix retains some flavor for longer. A dry mix works much the same as spices like cinnamon or chili powder.

For bottled salad dressings sold unrefrigerated, storage guidelines are pretty straightforward. As long as the bottle is unopened, you can keep it in the pantry or kitchen. Just make sure it’s not in direct sunlight or near sources of heat. This is because they can affect the quality of the ingredients.

Once the bottle is opened, always keep it tightly closed and in the refrigerator when not in use.

If you’ve made your favorite dressing from scratch and have some left over, it should go in the fridge as well.

If you’ve ever thought about freezing ready-made dressings, almost all manufacturers advise against it. The quality of the seasoning changes, and it will not be as good after thawing. But you can freeze meat or fish marinated in the dressing with great success.

Last but not least, let’s talk briefly about food hygiene. Remember to always use clean utensils when serving the dressing, and occasionally wipe the neck of the bottle with a dry paper towel. Following these practices will ensure that the dressing lasts as long as possible and will minimize the risk of microbial growth.

How long does salad dressing last?

Once again, let’s start with the dry mixes.

Each package comes with an expiration date on the label. And while the powder won’t go bad after that date, over time, the quality will degrade and some of the flavors will be lost. Therefore, it is better to use them in the months following that date. Opening the bag doesn’t make much of a difference, as long as you keep it tightly closed afterward.

When it comes to dressings that are sold unrefrigerated, they also come with an expiration date. And as long as the jar remains unopened, you can easily store that dressing past that date, even for a few weeks.

Once again, it is a matter of quality. The mix will not spoil soon after the date on the label, but its quality and freshness will gradually degrade over time.

Once the bottle is opened, its contents usually keep well between 3 and 6 months. But be sure to check the label for details, as this is a general guideline, not necessarily specific to what you’re dealing with.

Salad dressings sold refrigerated are much shorter than their shelf-stable counterparts.. They usually last a few weeks, maybe up to two months.

They come with an expiration or sell-by date, and that date is a pretty good indicator of how long the mix keeps well. Of course, it should keep for a week or two after that date, but don’t expect miracles.

Opening the bottle doesn’t usually change the shelf life much. Or to put it another way, you can keep the open mix up to or after the label date. But again, this is a general guideline, and you should refer to the manufacturer’s recommendation for a more precise period.

If you’ve made your own mix, it usually lasts 3-5 days, depending on the ingredients used. The more volatile the components, the shorter that period will be. If you have made a dressing using the dry mix, it should retain its good quality for about a week.

Please note that all of the above timelines are very general. Always check the dates and other conservation recommendations on the label of your dressing.

How to tell if salad dressing has gone bad

Let’s start with the dry mixes. In general, unless water gets into the package, the ingredients will most likely not spoil in a way that is unsafe to eat. But, like spices, they will gradually lose potency.

In the case of ready-to-use dressings, you have to look at quite a few things. First of all, the presence of mold or an unpleasant aroma. In either case, throw away the dressing. Ditto if it’s an oil-based dressing and it smells musty.

Now let’s talk briefly about separation.

If it’s an oil-based mix, like Italian or vinaigrette for your coleslaw (that’s how coleslaw lasts), oil separation is perfectly normal. Just shake the bottle well before serving, and it should blend evenly.

But if it’s a dairy-based salad dressing, like Ranch, blue cheese dressing, or anything with yogurt, separation is a sign of quality degradation. The dressing isn’t necessarily bad, but it probably won’t taste as good. Check the label to make sure the manufacturer recommends throwing it out or just giving it a spin.

If the dressing looks good, smells good, and you haven’t kept it much longer than recommended, it’s time to give it a try. Decide what to do with it based on its flavor.

If there is something that is not quite right, it is better to err on the side of caution and throw it away. Otherwise it sounds like you have a perfectly good salad dressing on hand.