Is Bacon Grease Compostable?

Although composting is a brilliant way to turn waste into valuable products, there are limitations to what can and cannot be composted. For those of us who eat bacon, we often find a large amount of oil/grease is produced during the cooking process, but what do you do with this oil? Is bacon grease compostable? 

Bacon grease is compostable but not in the same way as regular organic waste. The temperatures reached in home compost heaps are not high enough to effectively break down the molecular chains found in fats and oils and may lead to rot, pathogens, and pests.

Although disposing of bacon grease and other oils responsibly is exceedingly essential, they cannot, unfortunately, be composted in the same method as regular garden waste and kitchen (vegetable) scrap. Below we investigate some of these reasons; if there is a way to make them compostable, and what else you could do to reuse/recycle the grease?

Will Bacon Grease Compost Properly?

Bacon grease won’t compost properly in a typical open-air composting pile. Although smaller volumes of the oily/fatty substances won’t cause severe issues for your compost heap, adding excessive amounts to the pile is not advisable.

Places where you generally should not try to compost bacon grease include:

Places where you can compost bacon grease include:

  • Anaerobic decomposers
  • Large scale composting facilities
  • Municipal compost bins (some, and in small amounts)

Using Microbes for Composting Grease, Oil, and Fats

Microorganisms are responsible for decomposition. They take substantially sized waste products and, through their metabolic processes, convert them into usable compost. Some items are easier for these microbes to compost, while others, like bacon grease, are more difficult. 

Many microbes prefer not to break down the grease, so sunlight, rain, and other weather conditions fragment the grease particles into usable compounds before microbes can use them.

Although grease will eventually decompose over time, it takes much longer than plant-based materials/waste. Unfortunately, this time delay means you have a foul-smelling compost pile that attracts animals for a more extended period.

Some extensive commercial composting facilities are equipped to handle grease and other oils. They mix the oil/fats with wood shavings or other organic porous material. This material is added to one of the many windrows (a very long heap of decomposing material) and left to decompose.

These windrows are monitored and managed daily. They are frequently turned with tractors and other heavy machinery. They are also irrigated to ensure the correct factors for composition are balanced. 

The most important feature of these facilities is secure fencing around the perimeters and barriers to deter/trap scavengers attempting to get into the windrows.

Not all facilities are established to work with grease and oils, as it is time-consuming. 

Often, facilities which use a bio-digester and anaerobic decomposition would be more willing to take bacon grease. Although decomposition is still slower, the smells are trapped within, so pests are less of an issue. In addition, the organic waste is completely “digested” and produces a nutrient-rich “slurry.”

If you have the capacity for it, a home solar-powered bio-digester is also an option. These are used for plant and animal products which should not be placed on a regular compost heap.

Limitations of Composting Animal Products and Grease

There Is Not Enough Heat in Compost Heaps 

The most critical factor limiting the composition of bacon grease is heat. Unfortunately, a home compost heap does not reach the needed temperature to break down these oils and fats. 

Adding bacon grease to a community composting bin may also be frowned upon. The way these bins operate results in the grease shifting to a point where it is not exposed to enough sunlight, resulting in a slower decomposition rate. This also attracts animals to the bins.

Pathogens Are Resilient to the Composting Process

There are also numerous pathogens (disease-causing organisms) found in the tissues of animal products, which unfortunately aren’t killed by the lower heat the garden waste produces. These pathogens thrive in the warm, moist compost environment, breed, and spread through spores or water/soil. 

Grease Contributes to Oxygen Starvation and Blocks Water 

Aside from not getting hot enough, oils, fats, and grease also create a layer in the compost heap, which blocks air movement throughout the pile.

In composting, preventing your pile from becoming anaerobic (decomposition without the presence of oxygen) is critical in reducing awful smelling gas like methane from building up (and producing a high temperature). 

When fats and oils create a layer/barrier which blocks oxygen, the compost heap becomes oxygen-starved and moves towards becoming anaerobic.

Another issue with grease is that the oil layer it forms also acts as a barrier to water. Water and oxygen are critical within a compost heap, so by blocking it, composting efficacy is further reduced by blocking it.  

Avoid Attracting Pests

Another reason for not composting animal products is that the smell of the decomposing fats, oils, or animal products may also attract predators and scavengers like bears to your yard during composting. 

These opportunistic animals pose a threat to you and your family by their presence, as well as through potential diseases they may carry. Once pests know that your home is a haven for food, they move in and destroy not only your compost heap but most of your yard as well. 

Preventing pests from moving in is an essential aspect of compost management.

Other Uses for Bacon Grease

If you produce vast quantities of grease, oils, fats, and other substances which are not easy to compost, finding alternative uses for them is as vital as composting.

Below, we look at other end uses for bacon grease and other oils:

Burn the Extra Grease

After collecting and storing old grease for a significant time, one method to dispose of unwanted grease is to burn it in an outdoor fire pit. However, this option is risky, and permission must be obtained before attempting it. Also, make sure not to try this method during the dry season/droughts. 

You need to add the grease slowly to the fire and remain vigilant. A grease fire needs to be extinguished by smothering, so don’t let it get too big. 

Keep the Grease to Cook With

Although cooking with bacon grease is not a healthy option, the taste and waste reduction benefits are substantial. In addition, collected bacon grease is viable for cooking for over one month when stored in the freezer. 

Start by taking the leftover grease and straining it into a container to remove any larger particles. Make sure this container can seal. Then, close the container and pop it into the freezer to prolong the grease’s longevity and make cooking easier.

Add Some Animal Fats/Parts to Livestock Feed

If you have pigs or know someone with pigs, feeding them a small amount of oil/grease is also an option. The amounts are, however, limited.

Bury the Old Grease 

Taking the grease and burying it is a semi-viable way of dealing with the issue when all else fails. The hole needs to be deep enough that dogs, foxes, and other animals don’t try to dig it up.

It would be best to do this burying infrequently (once a year), and a new hole needs to be dug for the following grease collection in a different area.

Organisms living in the soil can break down the grease, oils, and fat but require time. Therefore spreading the grease in a more significant hole allows more surface area for the organisms to work.

Dispose of the Grease in Your Municipal Waste Green Bin

Instead of trying to compost bacon grease yourself, in most places, you have the option to send it with your municipal green waste to a facility that is better equipped to deal with it. 

This option for composting is limited to residential amounts of oils, fats, and grease produced, which is generally around half a gallon (1.89 L).

Before throwing the grease in the bin, make sure it is solidified, either by allowing it to cool to room temperature or by placing it in the refrigerator. Once hard, place the mass in a compostable or paper bag and secure the opening to prevent it from opening up accidentally. Then, place it in the green bin, or take it to a drop-off facility. 


Composting is a worthwhile endeavor, and while you can add bacon grease in minute amounts to your compost pile, anything closer to half a gallon may attract rodents, and other animal pests, while also slowing down the rate of the composition. A better option for bacon grease is to reuse it for cooking, and when you finally need to discard it, take it to professionals or invest in a solar digester.

Alexander Picot

Alexander Picot is the founder of and its lead content writer. He created the website in 2022 as a resource for horticulture lovers and beginners alike, compiling all the gardening tips he discovered over the years. Alex has a passion for caring for plants, turning backyards into feel-good places, and sharing his knowledge with the rest of the world.

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