Quick answer: A straightforward 6%-superfat tallow soap recipe uses 1,000 g rendered beef tallow, 132 g sodium hydroxide and 300 g distilled water. This is cold-process soapmaking, not a melt-and-pour project: sodium hydroxide can cause severe chemical burns, so use exact weights, suitable protective equipment and good ventilation.
Basic 100% tallow soap recipe
| Ingredient | Weight | Purpose |
|---|---|---|
| Clean rendered beef tallow | 1,000 g | The fat that becomes soap |
| Distilled water | 300 g | Dissolves the sodium hydroxide |
| Sodium hydroxide, at least 99% pure | 132 g | The alkali required for bar soap |
This reference formula is published by Australian soapmaker Eight Acres and by Lovely Greens as a 6%-superfat batch. Superfat is the portion of fat deliberately left beyond the amount the sodium hydroxide is calculated to saponify.
Do not change the fat, batch size or sodium hydroxide by guesswork. Different fats have different saponification values. Enter every changed formula into a reputable soap calculator and check the result before starting. Measure everything by weight, not cups or spoons.
Equipment for a safer setup
- digital scale that reads to 1 g or better
- chemical-resistant gloves and splash goggles
- long sleeves, long trousers and closed shoes
- heat-safe stainless-steel or suitable heavy-duty plastic containers
- stainless-steel spoon and stick blender reserved for soapmaking
- silicone or lined loaf mould
- thermometer
- clear, ventilated workspace with running water nearby
Do not use aluminium: sodium hydroxide reacts with it. Do not use fragile glass for the lye solution, because rapid heating and thermal shock can break it. Keep a copy of the sodium hydroxide supplier's safety data sheet accessible and follow its first-aid instructions.
How to make tallow soap by cold process
- Prepare the space. Remove food, children and pets. Put on gloves, goggles and protective clothing. Set the mould on a stable surface.
- Weigh separately. Weigh the tallow, distilled water and sodium hydroxide into separate suitable containers. Confirm every number before combining anything.
- Make the lye solution. In ventilation, slowly sprinkle the sodium hydroxide into the water while stirring. Never reverse the order. Avoid the hot vapour and set the covered, clearly marked container somewhere secure to cool.
- Melt the tallow. Warm it gently until fully liquid, then remove it from the heat.
- Bring both mixtures into range. Eight Acres mixed its tallow and lye solution at about 55°C. Keep the tallow liquid, but avoid overheating. Use your chosen tested method consistently.
- Blend to light trace. Carefully pour the lye solution into the melted tallow. Alternate short stick-blender pulses with hand stirring until the mixture thickens slightly and leaves a faint trail.
- Pour and protect. Pour into the mould without splashing. Keep the fresh soap inaccessible: it remains caustic during early saponification.
- Unmould and cut. Check after about 18 to 24 hours. Tallow makes a firm bar, so cut while it is solid but not yet brittle. If it still feels soft, wait and check again.
- Cure. Place bars with space between them in a dry, ventilated area for at least four to six weeks. Label the batch and keep it away from children and pets.
Can you make a smaller batch?
Mathematically scaling the table is easy, but small weighing errors matter more in a small batch. Do not simply halve a recipe and assume the result is safe. Run the exact fat weight through a soap calculator, verify the superfat setting and use a scale precise enough for the smaller sodium hydroxide amount.
Tallow soap troubleshooting
| What you notice | Likely issue | Safer response |
|---|---|---|
| Mixture separates in the mould | False trace, poor mixing or temperature mismatch | Do not use the batch on skin. Keep it secured and consult an experienced soapmaker before attempting a rebatch. |
| Bar is brittle when cut | It was cut too late, the formula was inaccurate or the batch lost too much water | Review weights and process notes; do not assume crumbling soap is safe. |
| Oily pockets or liquid remain | Separation or inaccurate measuring | Isolate the batch. Do not touch leaking liquid with bare skin. |
| White powder on the surface | It may be soda ash, but appearance alone cannot prove that | Do not diagnose an unknown batch by sight. Check records and seek experienced advice. |
| Orange spots or stale odour later | Fat oxidation or contamination | Discard the affected bar rather than trying to mask the smell. |
A pH strip by itself does not prove that an unfamiliar or separated soap batch is correctly formulated. Accurate records, a checked formula and a complete cure are the starting points; when in doubt, do not use the batch.
DIY tallow soap or a ready-made bar?
DIY makes sense if you already understand cold-process soap, have dedicated equipment and want control over a simple formula. It is a poor shortcut if you are uncomfortable with caustic materials or only want one bar.
The ready-made Tallow & Milk Soap is currently available for $20 in a 100 g bar. It uses a tallow-and-milk base with jojoba oil, aloe and vitamin E. For help choosing and using a bar, read the beef tallow soap Australia guide.
Frequently asked questions
How much sodium hydroxide do I need for tallow soap?
The cited 6%-superfat formula uses 132 g sodium hydroxide for 1,000 g beef tallow. Because the correct amount depends on the exact fat and desired superfat, check any variation in a soap calculator.
Does cold-process tallow soap contain lye?
Sodium hydroxide is required to turn fat into bar soap. A correctly formulated and fully saponified bar is not the same substance as the starting lye solution, but poor measuring or separation can leave an unsafe batch.
How long does tallow soap need to cure?
Allow at least four to six weeks in a dry, ventilated place. Curing lets water evaporate and the bar become milder, harder and longer lasting.
Can I add coconut or olive oil?
Yes, but not by adding it to this formula. A different oil blend needs its own sodium hydroxide calculation. Use a tested recipe or enter the complete blend into a soap calculator.
Can I make tallow soap without sodium hydroxide?
You cannot make soap from tallow without an alkali. If you want to avoid handling sodium hydroxide, use a commercial melt-and-pour base or buy a finished bar.
About Tallow and Honey
Tallow and Honey creates low-tox skincare with grass-fed tallow, raw honey, and simple ingredients chosen for dry, sensitive, and barrier-stressed skin. Explore our Tallow and Honey Balm or learn more about the brand.