Safrole makes up roughly 85% of the essential oil in sassafras root bark, and removing it completely at home is not straightforward. The FDA banned safrole as a food additive in 1960 after rodent studies linked it to liver cancer, which means any sassafras product sold for consumption in the U.S. must be safrole-free. Commercial producers accomplish this with organic solvent extraction, a process that is highly effective but not practical in a home kitchen. Still, there are ways to significantly reduce safrole content depending on how you prepare sassafras.
Why Sassafras Contains So Much Safrole
Sassafras root bark produces an essential oil that is approximately 85% safrole by weight, with small amounts of camphor (about 3%) and methyleugenol (about 1%) making up most of the rest. Safrole is what gives sassafras its distinctive sweet, root-beer-like aroma. Because the compound is so dominant in the oil, any preparation that extracts the oil efficiently will carry a heavy dose of safrole along with it.
Under federal regulation (21 CFR 189.180), food containing any added safrole or sassafras oil is considered adulterated. Sassafras bark itself is specifically called out when it’s used primarily as a vehicle for delivering safrole to another food, such as tea. This is why commercial sassafras flavorings go through industrial extraction to strip the compound out before the product reaches store shelves.
How Commercial Producers Remove Safrole
The industry standard involves agitating sassafras material with organic solvents that dissolve and pull out the essential oil, safrole included. Research at Clemson University confirmed that this method, referred to as the FDA method in their study, resulted in “little to no safrole content” in the final product. The solvents selectively dissolve the oil-soluble compounds, which are then separated and discarded, leaving behind the water-soluble flavor components.
This is how safrole-free sassafras extract ends up in commercial root beer and other beverages. The process requires laboratory-grade solvents, proper separation equipment, and careful handling, which puts it well outside the reach of typical home preparation.
What Traditional Boiling Actually Does
If you’re making sassafras tea the old-fashioned way, by simmering root bark in water, you do end up with less safrole than you might expect. The Clemson study compared traditional boiling to aggressive solvent agitation and found that the boiled tea contained about 628 ppm of safrole per 300 mL serving, while the agitated samples contained roughly 2,269 ppm. That means boiling produced about 3.6 times less safrole per cup than maximum extraction.
The reason is simple: safrole is an oily compound that doesn’t dissolve well in water. It has a boiling point around 233°C (451°F), far above the temperature of boiling water, so it doesn’t readily vaporize into steam at normal cooking temperatures. When you simmer root bark, you’re pulling mostly water-soluble compounds into your tea and leaving a good portion of the oil behind in the bark. Some safrole does make it into the liquid, carried by small oil droplets and steam, but nowhere near the full amount present in the bark.
This reduction is meaningful but not complete. A cup of traditionally prepared sassafras tea still contains roughly 188 mg of safrole. For context, the International Agency for Research on Cancer classifies safrole as a Group 2B carcinogen, meaning it’s “possibly carcinogenic to humans” based on strong evidence in animal studies. Rodent research has used doses of 30 to 120 mg per kilogram of body weight daily over 28 days to study its effects on liver DNA, and the compound consistently produces dose-dependent genetic damage at those levels.
Steam Distillation: Partial but Impractical
Steam distillation is a technique sometimes suggested for separating volatile compounds from plant material. It works by passing steam through the plant matter, which carries volatile oils into a condenser where they separate from the water. Standard steam distillation operates at around 100°C at atmospheric pressure.
For sassafras, steam distillation would pull safrole out of the bark and into the collected oil layer, not remove it from an existing tea. In other words, it’s a method for extracting safrole from the plant, not for cleaning it out of a liquid you want to drink. If your goal is a safrole-free tea, steam distillation works in the wrong direction: it concentrates the oil rather than leaving behind a clean aqueous product. You could theoretically discard the oil fraction and keep only the water, but the water phase from steam distillation carries very little of the flavor compounds that make sassafras appealing in the first place.
Practical Steps to Minimize Safrole at Home
No home method will produce a truly safrole-free sassafras preparation, but several choices reduce how much ends up in your cup:
- Use leaves, not root bark. Sassafras leaves contain far less essential oil than root bark. Filé powder, made from dried and ground sassafras leaves, has been used in Cajun cooking for generations and contains only trace amounts of safrole compared to root bark preparations.
- Boil briefly and strain well. Longer steeping extracts more oil. A short simmer followed by straining through a fine mesh or cheesecloth removes bark particles that carry residual oil.
- Skim the surface. Because safrole is oil-soluble and less dense than water, any oil that does leach out will tend to float. Skimming the surface of your tea after brewing and letting it cool slightly can remove some of the oil fraction.
- Use less bark. The relationship between bark quantity and safrole in the resulting tea is roughly proportional. Using a small piece of root bark for a large pot of water dilutes the safrole concentration in each serving.
Why Complete Removal Is Difficult
The core challenge is that safrole is deeply embedded in the essential oil of sassafras bark, and the flavor people associate with sassafras comes largely from that same oil. Removing safrole completely without industrial solvents means losing most of the characteristic taste. Commercial safrole-free extracts solve this by using selective chemical separation that preserves some flavor compounds while stripping out safrole specifically, a level of precision that requires analytical chemistry equipment to verify.
Without gas chromatography or a similar analytical tool, there’s no way to confirm how much safrole remains in a home preparation. The Clemson data shows that traditional boiling cuts the amount substantially compared to full extraction, but “substantially less” is not the same as “none.” If your goal is zero safrole, the only reliable option is purchasing a commercially produced safrole-free sassafras extract that has been processed and tested to meet FDA standards.