Title Image

Knowing Our Food: Scraps

Knowing Our Food: Scraps

Picture the last food scrap you threw away. Maybe you were dumping some potato peels in the trash, or composting the outer leaves of a cauliflower. Why did you throw it away? Was it for aesthetic reasons? Did you consider any of that food inedible? Did you have patience in that moment to think of a reason to keep it? Were you out of containers to store it in? There are a multitude of reasons why food ends up in the bin, but we hope this article can make it easier to give your food (waste) another chance.

Food waste, as we’ve explored in this series on food knowledge, is one of the most urgent yet avoidable contributors to climate change. Even a single apple that goes to waste due to poor storage strategies or aesthetic imperfections represents a loss of all its embodied energy. That is to say, all the water and land used to grow it, all the energy used to transport and store it, and all of the caloric energy it could have provided to someone are squandered. At such a small scale, it’s negligible, and yet when everyone believes that throwing away food is not a big deal, it leads to enormous quantities of waste that often end up in landfills, releasing methane (a potent greenhouse gas) into the atmosphere.

Check out this video for how to make these delicious recipes!

Reframing Fruit Scraps

One way to reduce food waste is to rethink what you consider food. Of course, this isn’t to say that you should go around eating nut shells and parts of food that leave you with indigestion, but some foods that we are taught to discard have great flavors and health benefits. 

On the most basic level, this applies to fruits with soft peels. Your apple, pear, peach, or nectarine skins can and should be eaten, but certain dessert recipes ask you to peel them, and in those cases, you can enjoy the peel by itself or use it in tea. Beyond those four, kiwi skin adds fiber and flavor when you eat it with the rest of the fruit, and dried pomegranate and hazelnut skin can be pulverized and added to smoothies or sprinkled on meals as a supplement. But fruit scraps don’t just have to be healthy; we highly recommend making treats out of your lemon and orange rinds. Although candied citrus rinds are great dipped in chocolate or sprinkled on cakes, the ones we made were devoured before they could make it to those stages.

More unusually, banana skins make a wonderful meat substitute in some recipes, like tacos or lasagna. Watermelon rinds make good pickles, but they can also be candied by cooking them in sugar syrup. If you make your own milk alternatives at home, you can use the strained almond, oat, rice, or cashew pulp for baking by replacing some of the flour in a recipe with pulp. (Be aware that milk pulp as a flour replacement will have an effect on the moisture and gluten content, so it only works in small ratios of pulp to flour and doesn’t work for difficult pastries, like croissants.) Another unusual recipe we tried was jam made out of passion fruit rinds. By boiling the rinds, taking the skin off, and mashing them with sugar, we cooked a slightly floral and astringent spread that goes well with bread or scones.

Vegetable Scrap Recipes

It’s helpful to rethink how you treat the scraps from your vegetables, too. Make sure not to waste delicious broccoli stalks or beet greens, and definitely don’t throw out the peels of your root vegetables. When a recipe requires peeled potatoes, the peels make a crispy snack or garnish when baked with some oil. Carrot greens transform into a delicious pesto when blended with oil, garlic, sunflower seeds, and salt.

Anything hard to chew can be blended into sauces, as is the case with kale stems and pea shells, and the stems of chard can be pickled. You can even sauté the tough green ends of leeks! The leaves of cauliflower, broccoli or romanesco broccoli should be cooked and eaten as well. Fava pods can be eaten whole, by grilling or sautéing them. When we tried out this recipe, we topped the pods with lemon juice, salt, chili flakes, and mint. 

It should go without mentioning that any vegetable scraps can be made into broth. Herb stems are superb for this purpose, but celery, onions, leeks, carrots, potatoes, and celery root all provide scraps to flavor your broth. Sometimes, there isn’t enough waste to produce broth, so these scraps can be stored in the freezer while you collect enough.

Similarly to broth, parts of some foods can be added to teas or infused on their own. This is most true for leaves, especially artichoke, persimmon, and strawberry leaves, and for dried or fresh citrus rind. 

Other Food Scrap Uses

Food scraps have purposes beyond just culinary! When making a vinegar-based cleaning solution for your house, lemon, orange and grapefruit rinds add a nice aroma. Banana skins serve as aphid repellents when they are chopped up and buried a couple inches deep around the base of a plant, and have anti-inflammatory properties when used on irritated skin. Coffee grounds and oat, almond and rice milk pulp are great body exfoliants, with rice and oat pulp having additional soothing properties when used on facial skin.

Many food scraps can be used to regrow foods, and these experiments double as educational projects as well. Root vegetables can be regrown by placing the tops of the root in water until new leaves begin to grow, at which point they can be planted in soil. Ginger pieces the size of an inch can be planted directly, and in very little time they will grow more ginger. Long, green vegetables such as celery, lemongrass, leeks, and green onions can be regrown by placing one inch of the bottom part of the plant (not counting the length of the roots) in a tray or glass of water until it begins to grow again. They can then be planted in soil. Leafy vegetables such as lettuce or endives undergo a similar process: the bottom parts are placed in water for several days or a few weeks until there is new growth and they can be moved to soil.

Scrap Dyes

We’ve saved the most exciting use for last: dyes! Many fruit and vegetable skins have tannins that help dyes bond well to natural fibers like cotton, linen, wool, or silk. The most well-known dyes made from food scraps are onion skins and avocado pits and skins. Yellow onion skins make yellow and orange dyes, red onion skins create colors between light lilac and deep magenta, and avocado scraps make a pink dye.

These dyes can be made stronger with alum powder, a mordant which helps dyes adhere to fabric better, but they can be used without it as well because of the presence of tannins in these food scraps. Some natural dyes, like the brown colors from chestnut and walnut shells, are vastly improved with the use of a mordant. Pomegranate rinds make a yellow dye and the leaves from loquat trees make a pink dye, both of which work best using a mordant.

Scraps in the Big Picture

Sometimes the scraps from your food just can’t be eaten or used, and that’s okay! When you get to this point, what’s most important is diverting your food waste from the landfill. If your city has a municipal composting program, you may have curbside compost pickup which is an easy way to reduce the emissions of your food waste, but you can also easily set up a compost in your own backyard, or get a small vermicomposting bin for your kitchen. Food waste can also be used to feed a biodigester, which produces biogas that you can use for energy. Both composts and biodigesters are part of our ongoing research at our production center, so you can expect an article soon about the merits and challenges of these systems in an urban setting. And lastly, if you do not have access to municipal or domestic compost where you live, you can see if any farmer’s markets or local gardens collect compost, and bring your food waste to them on a weekly basis. 

When it comes to food, there are so many systemic and cultural barriers to consuming it mindfully and avoiding waste. Overcoming preconceptions about food scraps that are seen as non-food is one part of working against these entrenched cultural beliefs that promote excessive waste. The problem, like any environmental issue, does not come down to just personal choices, but when these small changes are implemented at a wide scale, they can have significant effects, not just in the amount of food that goes to waste, but towards treating the food we have with respect. When we stop taking food for granted, we respect the seasonality of our produce, and stop letting vegetables go bad due to poor storage. You can read about these two related practices in the previous articles of our Knowing Our Food trilogy, and learn about how to preserve food for long or short periods.

Liked it? Take a second to support our reseach on Patreon!