Pine tar soap is made through cold process soapmaking, with pine tar added as a percentage of the total oil weight, typically between 10% and 15%. The process follows standard cold process techniques but requires some specific adjustments because pine tar accelerates trace dramatically and can turn your batter into thick, unpourable sludge within a minute if you’re not prepared. Here’s how to make it successfully.
Why People Make Pine Tar Soap
Pine tar has been used on skin for over 2,000 years. Hippocrates described it as a treatment in ancient Greece, and Scandinavian communities have been producing it since the Iron Age. The appeal is its soothing and antiseptic properties, which have made it a go-to remedy for eczema, psoriasis, seborrheic dermatitis, and other dry, itchy, inflamed skin conditions. Commercial pine tar soaps have been manufactured for well over a century, and many people make their own to control the ingredients and the concentration of pine tar in the bar.
Choosing Your Pine Tar
You want pine tar specifically, not coal tar. This distinction matters. Coal tar products have been classified as carcinogenic to humans by the U.S. Department of Health and Human Services, and creosote (found in coal tar) is classified as probably carcinogenic by both the EPA and the International Agency for Research on Cancer. Pine tar is a different product, derived from pine wood rather than coal, but you still want to buy from a reputable supplier that sells kiln-burned, wood-derived pine tar labeled safe for topical use.
Pine tar sold for veterinary or farrier use (hoof care) is widely available and commonly used by soapmakers. Look for 100% pine tar with no petroleum-based additives. It should be thick, dark brown to black, and smell distinctly smoky.
How Much Pine Tar to Use
Recipes dating back a century call for anywhere from 5% to 25% of the total oil weight. Most soapmakers settle on 10% to 15%, which gives a noticeable therapeutic quality without making the soap too dark or overwhelmingly smoky. If you’re making pine tar soap for the first time, 10% is a good starting point.
Some soapers argue that 20% is the minimum needed for real skin benefits. On the other end, commercial brands like Grandpa’s Pine Tar Soap use a smaller percentage (likely around 5%) and still get positive reviews from users with skin conditions. The right amount depends on your preference for scent intensity and how dark you want the finished bar.
One important note for lye calculations: pine tar does not saponify in a meaningful way. Soap calculators that list a SAP value for pine tar are misleading. What they’re really calculating is the tiny amount of lye that pine tar neutralizes, similar to how citric acid or vinegar would. Pine tar requires roughly 6 ounces of potassium hydroxide per 100 ounces, compared to over 25 ounces for the same amount of coconut oil. In practical terms, you should calculate your lye based on the actual oils in your recipe and treat pine tar as an additive.
A Reliable Base Recipe
Pine tar works well in simple, forgiving recipes. Since it accelerates trace so aggressively, you want a base that gives you the most working time possible. A good starting formula (by total oil weight, excluding pine tar):
- Olive oil: 40% to 50%, slows trace and produces a mild bar
- Coconut oil: 20% to 25%, adds lather and hardness
- Lard or palm oil: 20% to 25%, adds firmness and a creamy feel
- Castor oil: 5%, boosts lather
Run your oils (without the pine tar) through a lye calculator like SoapCalc or Soapee. Set your superfat at 5% to 8%. A higher superfat leaves more unsaponified oils in the bar, which can feel more moisturizing. Weigh your pine tar separately as an additive at 10% to 15% of the total oil weight.
Step-by-Step Process
Prepare your lye solution first. Slowly add sodium hydroxide to distilled water (never the reverse), stir until dissolved, and set aside to cool. Melt your solid oils, then combine them with your liquid oils.
Here’s where pine tar soap diverges from a standard batch. Warm your pine tar gently before adding it. You can set the container in a warm water bath until it becomes more fluid. Then stir the pine tar directly into your melted oils before adding the lye solution. Blending it into the oils first helps distribute it evenly and gives you slightly more control once lye enters the picture.
Bring both your oil mixture and your lye solution to around 120°F to 130°F. Temperature matters more here than in regular soapmaking. If your ingredients are too cool, solid fats can start to resolidify and create a false trace, where the batter looks thick but hasn’t actually emulsified. This leads to separation and a failed batch. Keeping everything at 120°F or above helps avoid that problem.
Pour your lye solution into the oil and pine tar mixture. Use a stick blender in short pulses, just a second or two at a time, stirring by hand in between. Pine tar accelerates trace so fast that experienced soapmakers report having less than a minute of working time before the batter becomes thick, unpourable brownie batter. You will not have time for swirl designs or elaborate molds. Work quickly and pour into your mold as soon as you reach a light to medium trace.
Dealing With Acceleration and Ricing
Pine tar can cause both acceleration (batter thickening too fast) and ricing (small, grainy lumps forming in the batter). Both are common, and neither necessarily means your batch is ruined. If your batter rices, keep stick blending in short bursts to smooth it out. If it accelerates past the point of pouring, you can glop it into the mold and press it down firmly with a spatula. The soap will still work, it just won’t look as polished.
Skipping fragrance oils and essential oils from the initial batch is smart for beginners, since fragrances can further accelerate trace. Get comfortable with how pine tar behaves on its own first.
Scent Options
Pine tar soap smells smoky. There’s no getting around it. Some people love the campfire quality, while others find it overwhelming. Lavender is a common first choice for masking the scent, but soapmakers report it doesn’t do enough to compete with the smokiness.
Stronger essential oils tend to work better. Patchouli, sandalwood, and tea tree oil all complement the earthy, resinous character of pine tar rather than fighting it. Pine essential oil is another logical pairing that leans into the woodsy profile. If you add essential oils, do so at trace, working fast, and expect the scent to mellow over the cure period.
Curing and Storage
After pouring into molds, insulate the soap lightly with a towel and let it sit for 24 to 48 hours before unmolding. Pine tar soap tends to be soft at first, so give it an extra day if it feels squishy when you press on it.
Cut into bars and cure on a rack with airflow for at least 4 to 6 weeks, the same as any cold process soap. Longer curing produces a harder, milder, longer-lasting bar. Some soapmakers prefer to cure pine tar soap for 8 weeks or more, finding the scent mellows and the bar firms up considerably. Flip the bars once a week so all sides dry evenly.
Finished pine tar soap ranges from dark amber to nearly black, depending on the percentage of pine tar used. The bars will have a distinctive smoky scent that softens over time but never fully disappears. Store cured bars in a cool, dry place. Like all handmade soap, they’ll last longest if kept out of standing water between uses.