Welcome to to Gravy Town. Pull up a chair, grab a ladle, and settle in. Gravy's our business and business is booming. No, seriously we reeeaaalllly love gravy at Extra Crispy HQ. Within the past couple of weeks, we've done gravy shots and gravy chasers (you'll hear more about that soon), choreographed a gravy dance, and boasted a working gravy fountain at our book launch party. We've mapped regional gravy styles across America, mastered a few of our favorites, and even came up with a rainbow gravy that's marginally less horrifying than it sounds. We can steer you toward your gravy destiny, but there is one part of the journey you're going to have to take alone: bringing it back to life after it's been in the fridge.
Weird stuff can happen to gravy if it’s left to sit around. Gravy is made through a process of starch gelatinization—basically the thing that happens when hot fat and starch are mixed together and start to thicken. The molecules form a network that traps water, and depending on what thickener was used (flour, cornstarch, etc.) and how the gravy is allowed to cool, it will form a gel of varying strength. If that gel is overheated, reheated too many times, or mixed with too much acid (say, in the form of vinegar or wine), the network will break down and things will get, scientifically speaking, kinda gross. The last thing gravy should ever bring you is sadness. Here are some measures you can take from the get-go.
First of all, consider how you contain your gravy during the initial meal. A gravy boat is festive as heck, but it also exposes a lot of the gravy's surface to air, causing it to cool at different rates. A lidded container is useful, especially a Thermos, which then affords you the opportunity to proffer a gravy Thermos to your guests throughout the meal. People also tend to leave gravy simmering in a pan on the stove while folks are eating, but that may lead to scorching on the bottom and gnarly, rubbery skin on top. If you must take this route, make sure the heat is as low as possible, periodically stir it from the bottom up, and cover the pan with a lid. Some cooks also cover the top of the gravy with lettuce leaves, and if that is your particular gravy truth, I will not deprive you of it.
After the meal, look into your heart. Assess if the gravy in the pan or serving vessel is truly worth saving. Gravy is a renewable resource that can and should be made whenever, not only on the holidays. If what's left over looks like something NASA would use to protect fragile human skin in the vacuum of space, say goodbye with love. If it's still a liquid and hasn't been sitting out for hours collecting bacteria, scrape or strain off any especially rubbery portions and pour the gravy into the smallest lidded container that will hold it. Or—perhaps ideally—dump it into a zip-top bag with as much air pressed out as possible. You may also freeze gravy for up to a month. Perhaps you should fill an entire shelf of your freezer with gravy, just in case.
When it is time to reheat the gravy, have a whisk on hand. The gravy must be brought to a temperature that will kill any bacteria that developed, but doing so may cause the structure to break down. So pour it into a pan, bring it to a boil, and whisk like mad to bring it back to the proper consistency. If the gravy has gotten all gummy, thin it out by streaming warmed stock into it while whisking diligently. If it thins out too much, just keep reducing it over heat, or slowly add a bit more of the original thickener. If your gravy is meant to come back to you, it will.