The SodaStream Hack That Actually Keeps Salad Greens Fresh Longer

We've all been there. You come home from the farmer's market or grocery store with fresh lettuce for a classic Caesar salad. But, if you don't make the dish right away, just a few days later your plans are scuttled by some wilted, slimy leaves. When it comes to tender greens, you're always in a race against time to use them before they go bad. There are many ways to keep them fresh, but one of the most interesting (and easy) involves injecting a little carbon dioxide (CO2) into the storage container.

To do this, you need a SodaStream or similar device. Start by placing your salad materials in a zip top bag. Seal it until it is mostly closed, but leave a small opening in the corner. Push the air out with a light touch, so that you don't damage the contents inside, and then fit the nozzle of the SodaStream into the hole. Pump some gas in until you can see the bag aerate, and then seal it completely. This little trick might extend the lifespan of your greens upwards of nine days, as opposed to the five days maximum you can usually expect.

To understand why this technique is successful as a means to extend the life of salad greens, it helps to look at why vegetables go bad in the first place. Have you ever heard that fruits and vegetables breathe? They both undergo a process called respiration, where plant matter takes sugar and oxygen and transforms it into CO2, which eventually deteriorates its structure. This process continues to occur after plants have been harvested, so reducing respiration is key to extending the shelf-life of produce. One of the reasons we store greens in the refrigerator, for example, is because cold temperatures limit respiration.

Another way to reduce this process is through packaging. One of several secrets about bagged salads you may be surprised to learn is that many manufacturers rely on what is called Equilibrium Modified Atmosphere Packaging (EMAP). With this method, greens are stored in containers that have perforated surfaces, giving them access to a calculated amount of oxygen that allows for maximum freshness while on store shelves. So, by using your SodaStream to inject CO2 into your salad materials, you're creating your very own EMAP. With a CO2-rich environment, the produce will undergo less respiration and stay fresh for a longer period of time.

If you don't own a SodaStream, there are still plenty of ways to keep your greens fresh for longer. For one, you can still introduce some CO2 by breathing into the bag before closing it up. Human breath contains carbon dioxide that you will transfer to the produce in much the same way the SodaStream works. The upside of this is that it doesn't require any fancy gadgets; the downside is that it's not exactly a hygienic option if you're serving salad to guests.

Another way to stop your lettuce from becoming slimy is by keeping it as dry as possible. Bacteria needs water to grow, so excess moisture will lead to spoilage. You can store your greens in a container with a paper towel, which will wick up the extra water. Similarly, you can run them through a salad spinner before storing to remove excess water.

You also want to consider the best place in your refrigerator to store salad. Always place greens at the top of the fridge. Doing so keeps them out of the coldest areas where the tender leaves are more prone to freeze. Just don't place them too far back on the top shelf, as this is where the air vents are usually located. Exposure to this area can also cause greens to wilt and freeze quickly.