Fridge or pantry? How to store peanut butter, ketchup and other staples
Tue., March 28, 2023
Refrigeration for some open items is optional, but sometimes recommended. (Rey Lopez/For The Washington Post)
Of all the little things that cause domestic squabbles around the house, where to store stuff has got to be at the top of the list. Who didn’t put their shoes back in the rack? Do we leave unopened mail on the dining room table or the kitchen counter?
Here’s another: Does the mustard go in the fridge or in the pantry?
The answer is not always so black-and-white. In fact, the suggested storage recommendations for a variety of other condiments, including peanut butter, hot sauce and even ketchup, inhabit a kind of gray area that has inspired plenty of confusion and disagreement.
Abby Snyder, an assistant professor of microbial food safety at Cornell University, says that’s because food storage recommendations are created to address two separate considerations: safety and quality. The difference between those rationales is rarely made explicit.
A lot of the guidance surrounding condiments revolves around quality, Snyder says. The idea is to prevent the food from deteriorating, whether that means separation, off flavors or spoilage. (Spoilage is a quality issue more than a safety one, though Snyder recommends discarding condiments with mold, as there is the risk it has spread throughout the entire jar, and some can create toxins.)
Food safety does not typically play into advice about storing condiments. Shelf-stable condiments are much less likely to support the growth of pathogens, disease-causing microbes that contribute to such foodborne illnesses as salmonella, E. coli and botulism, Snyder says. That can be explained by two factors: pH, or the measurement of acidity, and water activity, the amount of water that is available for microbes (not the same thing as moisture content). Higher water activity and less acidity tend to be more favorable for microbes. As to how this relates to condiments, these staples tend to be less hospitable to microbes because they are fairly acidic and/or low in water activity, since the water is bound up with high amounts of ingredients such as salt and sugar.
The fact that many of these condiments are fine on the counter but may last longer in the fridge can lead to varying or conflicting advice. Personal preference and ease of use – have you ever tried spreading cold peanut butter? – also comes into play. To help you sort things out, I’m taking a look at where you can store a few of the most common pantry staples.
Peanut butter is a low water activity product that is commonly stored at room temperature, Snyder says. It does not require refrigeration, but again, there are reasons to consider it, including a longer shelf life at higher quality. (While peanut butter has been tied to outbreaks of foodborne illness, that’s because once introduced in production, salmonella can survive in it, but not grow. Refrigeration at home would not have any bearing on this.)
Some people prefer to refrigerate natural peanut butter, as it is prone to separation, and cold temperatures can slow down that process. As with nuts and whole grains, refrigeration can also stave off rancidity in peanut butter, which can be more of a risk when it comes to the oil layer on top of separated natural peanut butter, Snyder says. The USDA’s FoodKeeper app recommends consuming refrigerated open natural peanut butter within four months, while other commercial varieties will be at their peak after opening for up to three months in the pantry and 12 months in the refrigerator.
“There are no ingredients in mustard that spoil,” according to manufacturer French’s. “While refrigeration will help maintain flavor, it’s not necessary to refrigerate if you prefer to consume your mustard at room temperature.” It specifically recommends refrigerating Dijon and horseradish mustard to preserve their distinct flavors. French’s says the flavor of refrigerated mustard is at its best for up to three months when refrigerated, while the USDA recommends refrigerated mustard be consumed within one year of opening.
It’s easy to see ketchup sitting out at a restaurant and wonder whether you’ve been wrong to have been refrigerating it all these years. In a word, no. Typically, those jars are just put out for service and/or refilled from a larger stash stored in the refrigerator. Like mustard, ketchup can be safely stored at room temperature, but “can” and “should” are two different things. Ketchup powerhouse Heinz has gone on record to state that the condiment’s natural acidity makes it shelf-stable. That stability, though, can vary based on storage conditions. “Refrigeration will maintain the best product quality after opening,” Heinz says. Consume ketchup within six months of opening, the USDA recommends.
Hot sauce is similar to ketchup and mustard, Snyder says, in that it is OK at room temperature but better maintains quality when refrigerated. The USDA only notes that hot sauce “will stay fresher longer if refrigerated,” while, for example, Cholula says its sauce is best used within six months of opening.
Molasses’s high sugar content makes it a low water activity food, making refrigeration unnecessary. Moreover, cold storage renders “it extremely difficult to use,” Snyder says. I’m sure I’m not the only one who has been stymied trying to measure thick, stringy, cold molasses. If you’re keeping score of other sweet syrups, honey should also be stored at room temperature (it crystallizes in the refrigerator), while open maple syrup is best refrigerated. The USDA recommends using open molasses within six months.
Like molasses, ghee is a real bear to deal with when it’s refrigerated. Cut to me chipping away at a block of it just to measure a few tablespoons. Ghee is a form of clarified butter, in which both water and the milk solids have been just about completely removed, meaning the likelihood of pathogens growing is low. So it’s OK to store it at room temperature, especially if you intend to use it within a few months and it’s in a cool, dark spot. Refrigeration is also fine, especially if you’re concerned about the fats going rancid. The FoodKeeper app does not offer guidance on ghee storage times, and manufacturer advice varies or does not mention specifics. One brand, 4th & Heart, generally recommends consuming ghee within three months of opening.
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