How to Compost Cooked Foods, Meats, and Dairy
By: Julie Day
Scavenger-proof containers make it easier to compost cooked foods.
Most general composting guidelines recommend against composting cooked foods. This may seem a little confusing – if something rots, it should be able to be composted, right? And it’s true, there are people out there composting anything and everything, from cooked foods to animal carcasses to “humanure.”
However, some items – including cooked foods – shouldn’t be composted unless you’re quite experienced. Cooked scraps, plate scrapings, meats, fats, and dairy present challenges that many “casual composters” won’t be prepared to handle, since these foods can:
- Smell Bad: Meats, fats, and dairy in particular can give off putrid odors as they break down. Plant scraps, on the other hand, tend not to cause as much of a stink.
- Attract Pests: Rats, bees, biting flies, bears, and other pesky scavengers are attracted to the smell, which can lead to a whole new set of problems!
- Turn to Mush: Cooked foods easily putrefy and turn mushy and gross, which is not only unpleasant but interferes with proper aeration of the pile.
- Go Anaerobic: Decomposing meats can produce anaerobic bacteria, which is the archenemy of a normal, aerobic compost pile. These bacteria can interfere with the composting process and cause problems with odors and acidity.
- Need High Heat: In order to kill harmful bacteria and break down proteins and fats, your compost pile needs to heat up properly, which requires attention and maintenance.
If you’re in the habit of simply tossing stuff into a compost pile to see what happens, you’re better off avoiding cooked foods. However, if you’re an experienced composter, go ahead and give it a try – if it’s made of (or comes from) living things, it’s possible to compost it if you keep the following in mind.
How to Compost Cooked Foods
- Cooked Vegetables: The “no cooked foods” rule is a general guideline because many of us add fat, butter, or meat products to our cooked veggies. Pure steamed veggies – with no oils or sauces – should compost just fine, especially if they’re well mixed into the pile. Don’t forget the cooking liquid, too!
- Cooked Starches and Grains: If you’re composting cooked veggies with no problem, consider adding cooked rice, pasta, and bread to the pile. Some gardeners believe that these foods attract scavengers more readily than their uncooked counterparts, but every yard is different.
- Meats, Fats, Oils, and Dairy: If you are successfully composting other cooked foods in a hot, well-aerated compost pile, you’re ready to give meat a try! Be sure to pre-cook raw meat scraps to kill salmonella and other dangerous bacteria. For best results, chop or puree meat scraps to help them mix in and break down.
Tips for Successful Composting
Composting cooked foods requires that you be a little more attentive to your compost pile. To keep it scavenger-free and to make sure it’s hot enough to kill disease pathogens, follow these tips:
- Keep It Hot: Use a thermometer to make sure your pile reaches at least 140°-160° F for a week or more. Turn your compost regularly to keep the temperature up.
- Bury It: Cover cooked foods with a few shovelfuls of dirt, leaves, or sawdust in your compost pile to keep smells down and discourage pests.
- Enclose It: If scavengers are a problem, use a critter-proof enclosed system such as a tumbling composter or wormery.
- Go Anaerobic: Anaerobic fermenting systems, such as Bokashi bins, use special bacteria in an airtight container. These types of composting systems can quickly and effectively break down meat and dairy scraps, although the resulting compost is more acidic than regular (aerobic) compost.
- What Happens during Composting (Food & Fertilizer Technology Center)
- How to Compost Eggshells, Meat, and Sour Milk (cleanairgardening.com)
- Bokashi: This Is Not Your Father’s Compost (cleantechnica.com
- Composting to the Ultimate (angelfire.com)
- Making Compost (Decision Time) (composterconnection.com)
- What Can I Compost?
- Benefits of a Compost Bin in Your Kitchen (video)
- How to Build a Compost Bin (article)