Homemade soap can last anywhere from 3 weeks to several years depending on the recipe, ingredients, and storage method. With proper care and storage, most homemade soaps will last 4-6 months. There are several factors that affect the shelf life of homemade soap including the type of oils used, additives, water content, and curing time.
What affects the shelf life of homemade soap?
There are four main factors that determine how long homemade soap will last:
1. Oil/Fat Type
The types of oils and fats used in homemade soap affect its shelf life. Soaps made with a higher percentage of saturated fats like coconut oil, palm oil, tallow, or lard tend to last longer than those made with more unsaturated oils like olive, sweet almond, avocado, or canola. Saturated fats are more stable and resistant to rancidity which gives the soap a longer shelf life. Unsaturated fats can go rancid faster especially when exposed to air, light, and heat.
2. Additives
Certain additives can extend the shelf life of homemade soap. Using all-natural antioxidants like vitamin E, rosemary extract, or green tea can help prevent oils from going rancid. Some soap makers also add chelators like tetrasodium EDTA which help prevent metals in hard water from oxidizing oils. Adding honey, beeswax, or sorbitol/glycerin helps lock in moisture which keeps bars from drying out and cracking over time.
3. Water Content
Homemade soaps with a lower liquid to oil ratio tend to last longer. The more water in the recipe, the faster excess moisture evaporates as the soap cures and leaves it brittle. Most soap makers use a 25-30% liquid to oil ratio for optimal longevity. A drier bar with minimal water will have a longer shelf life.
4. Curing Time
Allowing homemade soap to cure for 4-6 weeks after being made also extends its shelf life. During the curing process, excess moisture evaporates and the soap molecules rearrange themselves creating a more dense bar. Soaps that are used immediately may still feel soft or mushy. The longer homemade soap has to cure, the lower the water content will be over time.
How to extend the shelf life of homemade soap
Properly storing and caring for your homemade soap is key for longevity. Here are some tips to make your bars last longer:
- Allow 4-6 weeks minimum to cure before use.
- Wrap bars tightly in wax paper or freezer paper right after cure.
- Store in a cool, dark place with consistent mild temperature.
- Avoid storing soap in areas with heat, humidity or direct sunlight.
- Use within 3 months for soaps with high olive, avocado or canola oil.
- Use within 6 months for soaps with more coconut, palm or tallow.
- Do not let soap sit in water between uses.
- Cut bar in half once it gets thin around 3-4 months.
- Rebatch old soap with fresh soap for renewed shelf life.
How to tell if homemade soap has expired
Homemade soap that has gone bad typically shows some of these signs:
- Change in color or texture – soap may darken, become thickened or goopy.
- Spots or discoloration appear – can signal mold or excess fat turning rancid.
- Shrinking or cracks form – from loss of moisture as soap dries up.
- Warping or bending shape – due to aging and binding agents wearing down.
- Smell goes rancid or rotten – due to unsaturated oils turning bad.
- Development of white powder or crystals on surface – called soda ash, caused by excess moistures evaporating.
- Dries out faster and gets brittle or mushy – moisture loss as it ages.
- Does not lather well or feels gritty.
- Causes skin dryness or irritation.
If your homemade soap shows signs of aging, it’s best to throw it away and replace it with a fresh bar. Expired soap not only loses effectiveness but could also harbor bacteria and be unsafe to use on skin.
Average Shelf Life of Homemade Soap by Oil Types
The main oils and fats used to make homemade soap have varied shelf lives. Here is an estimate for how long bars made with different oil compositions typically last:
| Oil/Fat | Shelf Life |
|---|---|
| Coconut Oil | 9-18 months |
| Palm Oil | 6-12 months |
| Olive Oil | 3-6 months |
| Canola Oil | 3-6 months |
| Sunflower Oil | 3-6 months |
| Safflower Oil | 3-6 months |
| Sweet Almond Oil | 3-6 months |
| Avocado Oil | 3-6 months |
| Shea Butter | 6-12 months |
| Cocoa Butter | 6-12 months |
| Tallow/Lard | 9-18 months |
As shown, soap made with more saturated tropical oils like coconut, palm and tallow will last longer. Olive, almond, avocado and other vegetable oil soaps have a shorter shelf life around 3-6 months. Combining longer lasting fats with antioxidants and proper storage can help extend homemade soap duration.
Does homemade soap expire or go bad?
Technically, handmade soaps don’t really expire in the sense of food going rotten or becoming unsafe to eat. However, homemade soap does degrade in quality and effectiveness over time. The stability of the oils and fats decreases, moisture evaporates, and preservatives become less potent. This causes homemade soap to lose its fragrance, lather, and skin benefits after several months to a year.
If kept excessively long past its prime, homemade soap can spoil and potentially grow mold, bacteria or even pathogens that cause health issues. Storing soap in a cool, sealed container helps prevent contamination. But homemade soap that’s aged over a year and shows any signs of spoilage should not be used.
Can old homemade soap be rebatched?
Instead of throwing out old bars, you can give expired homemade soap a new life through a process called rebatching. This involves grating or shredding old soap into flakes or chunks. The soap pieces are then melted down with a bit of water or milk over low heat until it forms a smooth, pudding-like batter.
At this point, you can add fresh fragrance, essential oils, botanicals, clay or other addons to your preference. Pour the rebatched soap into molds to set, and allow curing as you would with fresh cold process soap. Rebatching resuscitates old soap by creating a renewed bar with moisture and ingredients.
Signs your rebatched soap went bad
Like regular homemade soap, rebatched soap can also deteriorate in quality after a while. Signs that your rebatched soap may need to be discarded include:
- Odd or rancid smell
- Grainy texture
- Dull, faded look
- Shriveled appearance
- Doesn’t lather properly
- Irritates skin or causes dryness
- Appearance of molds or fungi
- Excessive soda ash or crystallization on surface
For best results, use rebatched soap within 4-6 months. Adding a higher proportion of fresh oils and discarding soap that seems very old or rancid will give rebatched soap a longer lifespan.
Tips for making homemade soap last longer
You can help extend the shelf life of your homemade soap with these tips:
- Use more hard oils high in saturated fats like coconut, palm, tallow/lard or shea butter.
- Limit delicate oils prone to rancidity like canola, sunflower, olive, avocado.
- Add all-natural preservatives like rosemary extract, vitamin E or honey.
- Cure soap for a full 4-6 weeks before using.
- Store soap in a cool, dry place away from light and heat.
- Wrap tightly in freezer paper or wax paper right after cure.
- Avoid adding ingredients prone to spoilage like dairy milk or fruits.
- Use soap within 3-4 months for vegetable oil bars.
- Use soap within 6 months for palm, coconut or tallow bars.
- Cut bars in half as they get thin around 3 months.
- Rebatch old soap with fresh oil and lye mixture.
- Discard soap that smells odd, feels gritty or shows any molds.
What is the best way to store homemade soap?
Storing your homemade soap properly is one of the biggest factors determining how long it will last. Here are some tips for optimal soap storage:
- Cure soap 4-6 weeks before storage.
- Wrap tightly in freezer or wax paper after cure to retain moisture.
- Place wrapped bars in an airtight plastic container or food storage box.
- Store in a cool, dark cabinet or closet around 60-75°F temperature.
- Keep soap away from heat, humidity, sunlight, and direct air flow.
- Avoid storing soap in the refrigerator or freezer.
- Stack bars loosely in storage box, don’t cram tightly.
- If storing multiple fragrances, keep bars separated or they can absorb scents.
- Write date soap was made on boxes or bags.
- Use oldest soaps first and add new batches to back of storage container.
Following these homemade soap storage guidelines will help keep your bars looking and smelling great for months beyond initial cure time.
Does handmade soap get better with age?
Unlike wine or cheese, handmade soap does not improve with age. In fact, the quality and performance of homemade soap gradually decreases the longer it sits after cure. Why won’t soap get better over time?
- Fragrance oils and essential oils fade and evaporate.
- Textures can become thicker, clumpier or runnier.
- Bars lose moisture and become brittle or warped.
- Saponified oils degrade and stop producing rich lather.
- Colorants and botanicals oxidize and dull in hue.
- Preservatives lose potency to prevent rancidity.
- Bacterial growth is more likely on old soap.
For best lather, scent, and skin feel, homemade soap should always be used within 6 months of cure. The prime sweet spot is 1-2 months after initial 4-6 week cure.
Can you use homemade soap past its expiration?
It’s not recommended to use homemade soap that is past its expiration or shows signs of aging. Even if there’s no visible mold, old homemade soap carries risks:
- May harbor invisible bacteria that can cause infections.
- Higher chance of contamination the longer it sits.
- Can irritate skin, cause dryness, itching, and inflammation.
- Waste of money since it won’t lather or cleanse well.
- Health hazards if made with spoiled milk or plant purees.
- Higher risk of triggering allergies or sensitivities.
Expired homemade soap may still look perfectly normal but have excess bacteria below the surface. It’s not worth the risks of skin irritation and potential illnesses. Out with the old, in with the fresh new batch!
Does microwaving rejuvenate old soap?
Some people claim you can zap bar soap in the microwave for 10-15 seconds to re-melt and revitalize it. In theory this steams the soap to make it smoother, creamier, and like new again. However, there are some risks to microwaving handmade soap:
- Can dramatically heat up metal molds or inserts.
- Overheating soap can scorch or ignite natural ingredients.
- Soap may become too hot or bubbly and make a mess.
- Doesn’t extend shelf life, soap still continues to age.
- Essential oils and fragrance notes can change or burn off.
- Bacteria isn’t destroyed and may multiply faster.
A better option than microwaving old soap is to rebatch it on the stove or double boiler. This evenly melts soap at lower temperatures to safely renew soap when it expires.
Conclusion
With proper storage and ingredients, most homemade soaps can last 4-6 months or longer. Saturated oils like coconut and palm give soap a longer shelf life than delicate olive or almond oils. Natural antioxidants, a low water content, and full cure time also help homemade soap remain stable. Check for signs of aging like smell, texture, and appearance. Rebatch old soap for renewed freshness. Discard homemade soap past 6-12 months old to ensure best quality and safety.
