Romaine lettuce, a closely related cousin of the common standard lettuce, is a vegetable that presents vertical green leaves and a sturdy heart. Used in much the same way as ordinary lettuce, romaine lettuce is distinct from its cousin only by its marked resistance to heat1.
Yes, romaine lettuce holds up well to the process of freezing, and is best preserved at a temperature of 32°F 2, or precisely the freezing temperature of water. While romaine lettuce is more tolerant to the cell damaging effects of freezing than other leafy vegetables, it will still suffer a loss of quality once defrosted.
Can you Keep Romaine Lettuce on the Counter?
In short, the answer is a resounding no. Romaine lettuce, if not stored immediately after purchasing from a market, must be consumed in its entirety to avoid spoilage.
According to independent studies performed by researchers, most if not all species of lettuce will expire within two hours of being left out in room temperature conditions3. This means that no – romaine lettuce will not keep shelf-stable if left on the counter.
For signs that your romaine lettuce has begun to spoil, refer to the end of this article.
Can you Keep Romaine Lettuce in the Fridge?
A far smarter course of action than simply leaving your lettuce on the counter-top, choosing to refrigerate your romaine lettuce is both simple and effective.
In order to refrigerate romaine lettuce, first remove the vegetable from its original packaging. Wash thoroughly, taking care to dislodge any dirt or stray insects that may be present. In the event that the ends of the leaves show signs of mold or other types of fungi, simply remove the particular leaf.
Once meticulously cleaned, pat the romaine lettuce dry with a tissue or cloth. Seal the now-dry lettuce in an air-tight plastic bag free of any moisture, then situate in the refrigerator.
By following these simple steps, the romaine lettuce should remain edible for up to seven days in the crisper compartment of your fridge.
How Long Can Romaine Lettuce Last in the Freezer?
If frozen at the ideal time, as well as subjected to the appropriate procedures, romaine lettuce can last as long as six months in the freezer, though not without the texture being compromised.
Choosing to freeze your romaine lettuce is the best possible choice for purposes like making shakes or soups, but less so should you wish to use the leaves in salads or sandwiches.
Equipment Needed to Freeze Romaine Lettuce
Much like freezing other forms of lettuce, very little equipment is needed in order to prepare and store romaine lettuce. All that is needed is an appropriately large resealable plastic bag, a paring knife and a freezer.
Freezing the Romaine Lettuce
To begin freezing your romaine lettuce, the first step is to thoroughly wash the leaves. Remove any debris left over from the farm as well as any insects and dirt present.
Once washed, use your paring knife to remove the hearts of the individual leaves so as to leave only the green portion of the leaves. Make certain that any spots showing signs of fungal colonization or spoilage are removed. This step is optional if you wish to store the plant in its entirety.
Dry the freshly cut or whole leaves on a drying towel or tissue, ensuring that no excess water is clinging to the surface of the leaves and stalks. This will both prevent the leaves from fusing once frozen, as well as help preserve their quality.
Now dried, place the romaine lettuce together in your resealable plastic bag. Gently push out any excess air in the bag, taking care not to damage the leaves.
Place in the freezer to keep edible for up to six months, though keep in mind that the quality will suffer before this point in time.
How to Thaw the Romaine Lettuce
In order to thaw your romaine lettuce, simply remove from their plastic packaging and place on a cloth or set of tissues at room temperature for one hour.
Do not attempt to defrost the romaine lettuce in the microwave, as this will completely ruin the texture and taste of the vegetable.
What Can Frozen Romaine Lettuce be Used for?
As previously mentioned in this article, the act of freezing romaine lettuce can have a negative effect on the consistency and texture.
Because of this, the best way to use thawed romaine lettuce is in shakes and sauces, as the altered texture will have no bearing on these dishes.
Can Blended Romaine Lettuce be Frozen?
In the event that you have already chosen what to do with your romaine lettuce, it is entirely possible to blend and freeze the romaine lettuce ahead of time.
After washing the romaine lettuce, blend it to an even consistency and place in an air-tight container. Ensure that approximately one inch of open space is present between the container lid and the blended lettuce, in order to account for expansion of the liquid.
How to Know if Romaine Lettuce has Gone Bad
Signs of spoilage in romaine lettuce are most often immediately apparent.
Discoloration and darkened patches along the leaves are usually a sign of bacterial colonization, and the appearance of slime along the heart and stems should warrant an immediate disposal of the vegetable.
Apart from visual indications of spoilage, the presence of any sort of odor can also act as a warning sign. As lettuce often has no scent at all, if you notice a sour or bitter odor, it is best to assume that the romaine lettuce has begun to expire and should be thrown away.
1. Sydney C. Holmes et al. (July 2019) Selection of Heat Tolerant Lettuce (Lactuca sativa L.) Horticulturae https://doi.org/10.3390/horticulturae5030050
2. Marita Cantwell, Trevor Suslow (August 2001) Vegetables Produce Facts English, Lettuce, Romaine Department of Plant Sciences, University of California, Davis
3. Yaguang Luo, Arvind Bhagwat. (July 2008). Safe Leafy Greens—Before & After Bagging. Agricultural research magazine