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Can I leave bacon grease in the pan overnight?

Leaving bacon grease in a pan overnight is generally not recommended. Bacon grease left at room temperature can go rancid quickly and potentially harbor bacteria. However, there are some steps you can take to safely store bacon grease overnight if needed.

Quick Answer

It’s best to avoid leaving bacon grease in a pan overnight. To safely store, strain into an airtight container and refrigerate or freeze. Bacon grease can be kept refrigerated for up to 1 month or frozen for up to 6 months.

Can Bacon Grease Be Left Unrefrigerated Overnight?

Bacon grease should not be left out at room temperature overnight. Like any fat or oil, bacon grease can go rancid if left unrefrigerated for too long. The proteins and salts in bacon grease also make it prone to bacterial growth when left out.

Food safety experts recommend refrigerating bacon grease within 2 hours of cooking. If left out longer, the bacon grease can become a haven for bacteria and microbes that cause food-borne illnesses.

How Quickly Does Bacon Grease Go Bad?

The exact timeframe for how quickly bacon grease can go rancid depends on factors like:

  • Storage temperature – Grease left out at room temp will go rancid faster than grease refrigerated.
  • Cooking temperature – Grease from bacon cooked at higher temps keeps longer.
  • Meat quality – Better quality bacon fat lasts longer.
  • Container – Grease in an airtight container keeps longer.

As a general guideline, bacon grease left out at room temperature will start to go rancid within 8-12 hours. The grease can develop sour, bitter, or off flavors.

In the refrigerator, bacon grease can last for up to 1 month before going rancid. For maximum freshness and shelf life, bacon grease can be frozen for up to 6 months.

Can You Get Sick from Rancid Bacon Grease?

You likely won’t get severely sick from ingesting rancid bacon grease. The biggest risk is an upset stomach from the unpleasant tastes and smells.

However, bacon grease left out too long poses a more dangerous food poisoning risk. Bacteria like Salmonella, Listeria, and E. coli can grow in old bacon grease, especially if bits of meat are present.

Foodborne pathogens can multiply quickly at room temperature. Just a small amount of contaminated grease might contain millions of bacteria. If you used this grease for cooking, the bacteria could then contaminate your food.

Most Common Bacon Grease Bacteria

Here are some of the most concerning bacteria that can lurk in old, unrefrigerated bacon grease:

  • Salmonella – Causes salmonellosis, with symptoms like diarrhea, fever, and abdominal cramps.
  • Clostridium perfringens – Causes diarrhea and abdominal cramps.
  • Bacillus cereus – Causes vomiting and nausea.
  • Staphylococcus aureus – Causes severely upset stomach and diarrhea.
  • Listeria monocytogenes – Causes listeriosis, with fever, muscle aches, and nausea.

Proper refrigeration prevents these and other dangerous bacteria from growing. Cooked bacon grease should always be stored covered in the refrigerator or freezer.

Can You Save Bacon Grease That Was Left Out Overnight?

It’s generally not recommended to try to save bacon grease that’s been left out overnight and reached room temperature. At this point, it’s best to discard it.

Even if the grease doesn’t smell rancid, you can’t know for sure if harmful bacteria has multiplied. Storing old grease is not worth the risk of foodborne illness. When in doubt, it’s better to play it safe and throw it out.

Should You Strain the Grease First?

You may be tempted to save bacon grease by straining out any meat bits first, then refrigerating. However, this may not make the grease safe for reuse. Bacteria can quickly grow in grease even without solid particles.

For bacon grease you want to save, always strain and refrigerate it shortly after cooking, within 1-2 hours. Don’t take chances storing grease left out overnight, even if strained.

How to Safely Save and Store Bacon Grease

To safely save bacon grease for later use:

  1. Start with high-quality bacon and cook until crispy.
  2. After cooking, let the grease cool just slightly so it’s still warm and liquid.
  3. Pour the grease through a strainer into an airtight container, leaving any food particles behind.
  4. Let cool to room temperature, then cover and refrigerate.
  5. Use within 1 month for best quality and freshness.
  6. For longer storage, freeze bacon grease for up to 6 months.

Storing the strained grease in a covered glass jar or metal tin helps prevent oxidation. You can also use freezer-safe plastic bags. Make sure to label the container with the date.

Shelf Life of Refrigerated and Frozen Bacon Grease

Storage Method Shelf Life
Refrigerated 1 month
Frozen 6 months

These timeframes assume the bacon grease was fresh when originally stored and kept consistently chilled. Discard any grease that smells off or rancid when thawed or reheated.

How to Discard Bacon Grease

Bacon grease should never be poured down the drain. When cooled completely, transfer the grease to an empty can or jar and throw away with other food waste. Wiping out excess grease with a paper towel first helps minimize clogs.

If you have a high efficiency garbage disposal, small amounts can be ground up. But avoid making a habit of pouring fats down the drain. Grease is a common cause of clogged pipes and sewer problems.

Some municipalities allow pouring fats into compost collection. Check local guidelines before adding bacon grease to a compost bin.

Can Bacon Grease Be Composted?

Bacon grease can technically be added to compost in small amounts. However, too much grease can attract pests and rodents when composting.

For a compost pile at home, limit bacon grease to a few tablespoons per week. Mix some brown materials like dried leaves into the pile to help break down the grease.

Industrial compost facilities may have more capacity to safely compost fats. But avoid adding bacon grease to workplace or community compost unless allowed in the posted guidelines.


Leaving bacon grease sitting out overnight can lead to rancidity and bacterial growth. For food safety, bacon grease should always be cooled, strained, and refrigerated within 2 hours of cooking.

Storing the grease in an airtight container helps extend the shelf life. Properly stored bacon grease keeps for 1 month in the fridge or 6 months in the freezer.

To prevent clogged drains, bacon grease should be discarded in the trash once it’s cooled off. Small amounts can also be composted, depending on local guidelines. But it’s wisest not to take risks storing grease that’s sat out too long.