SDA 40-B is specially denatured alcohol made by adding, to every 100 gallons of ethyl alcohol, one-sixteenth avoirdupois ounce of denatonium benzoate, N.F. and one-eighth gallon of tert-butyl alcohol, as specified in 27 CFR 21.76. Fragrance and personal care formulators prefer it because both denaturants are used at extremely low levels and neither one adds the solvent odor that methanol- or isopropanol-denatured grades carry into a finished scent. You still need a TTB industrial alcohol user permit to buy it.
What is actually in SDA 40-B?
Denaturing is the process of adding a substance to ethanol that makes it unfit to drink so the alcohol can be sold free of the federal beverage excise tax. Most formulas do that with a bulk solvent. SDA 40-B does it with a bitterant instead, which is why the additions are so small.
| Denaturant | Amount per 100 gal ethanol | What it does |
|---|---|---|
| Denatonium benzoate, N.F. (Bitrex) | 1/16 avoirdupois ounce | Extremely bitter compound; makes the alcohol undrinkable at trace concentration |
| tert-Butyl alcohol | 1/8 gallon | Secondary denaturant and analytical marker |
Add those together and roughly 99.9% of the finished volume is still ethyl alcohol. That is the whole point of the formula: maximum ethanol, minimum interference.
Why fragrance formulators choose SDA 40-B
Perfume, cologne and body spray are built on an alcohol base that can be 60 to 90 percent of the bottle. Anything the denaturant contributes in odor, drydown or skin feel shows up in the finished product. Compare the practical impact:
| Formula | Denaturant load per 100 gal | Odor impact | Typical fit |
|---|---|---|---|
| SDA 40-B | 1/8 gal tert-butyl alcohol plus 1/16 oz denatonium benzoate | Minimal | Fragrance, cosmetics, topical personal care |
| SDA 39-B | 2.5 gal diethyl phthalate plus 1/8 gal tert-butyl alcohol | Low, but adds a phthalate | Legacy cosmetic formulas |
| SDA 3-A | 5 gal cyclohexane or methyl alcohol | Noticeable solvent character | Industrial solvent, lab reagents |
| SDA 3-C | 5 gal isopropyl alcohol | Noticeable solvent character | Coatings, cleaning, processing |
There is a second reason beyond odor. Many brands have spent the last decade reformulating away from phthalates, and SDA 39-B carries 2.5 gallons of diethyl phthalate per 100 gallons. SDA 40-B delivers a comparably clean sensory profile without it, which is why so much of the personal care market has migrated to it.
Authorized uses for SDA 40-B
TTB does not let you use a specially denatured alcohol formula for whatever you want. Each formula in 27 CFR Part 21 carries a list of authorized use codes, and SDA 40-B is written for topical and household products:
- Hair and scalp preparations, shampoos, soaps and bath preparations
- Lotions and creams for hand, face and body
- Body deodorants, perfumes and perfume tinctures, toilet waters and colognes
- External pharmaceuticals that are not U.S.P. or N.F.
- Disinfectants, insecticides, fungicides and other biocides
- Cleaning solutions including household detergents, room deodorants and theater sprays
- Inks, miscellaneous solutions, and product development or pilot plant work for your own use
Notice what is absent: SDA 40-B is not authorized as a fuel, and it is not the formula for ingestible or internal pharmaceutical products. If your application falls outside this list, the answer is a different formula, not a workaround.
Do you need a permit to buy SDA 40-B?
Yes. Every specially denatured alcohol formula, SDA 40-B included, requires a TTB Industrial Alcohol User Permit before a supplier can ship to you, and your permit has to cover the specific formula and use code. That is the single biggest difference between SDA and completely denatured alcohol such as CDA 12-A, which ships without a federal permit. We walk through the whole process in our guide on whether you need a TTB permit to buy denatured alcohol, and the formula landscape more broadly in what denatured ethanol is.
Proof and grade options
SDA 40-B is a denaturing formula, not a proof specification, so you choose the base ethanol underneath it. Two options cover nearly every fragrance and cosmetic program:
- 190 proof ethanol at roughly 95% ethyl alcohol by volume, which sits at the ethanol-water azeotrope of about 95.6% ethanol by weight. This is the workhorse for most water-tolerant formulas.
- 200 proof ethanol, dehydrated past the azeotrope to under 0.5% water. Specify this when residual water will break an emulsion, cloud a formula or interfere with a reaction.
Pristine Alcohol produces both from 100% Michigan corn in an all-stainless-steel plant in Marysville, Michigan, and supplies SDA 40-B denatured ethanol in drums, totes and tankers.
Frequently asked questions
Is SDA 40-B the same as Bitrex alcohol?
Bitrex is a common trade name for denatonium benzoate, the bittering agent in SDA 40-B. Calling it “Bitrex alcohol” is informal shorthand. The regulatory name is Specially Denatured Alcohol Formula No. 40-B, defined at 27 CFR 21.76.
Can SDA 40-B be used in products people ingest?
No. Its authorized uses are topical and household. Ingestible and internal pharmaceutical applications require undenatured, tax-paid alcohol or a different regulatory path entirely.
What is the difference between SDA 40-B and SDA 40-A?
Both use one-eighth gallon of tert-butyl alcohol per 100 gallons, but SDA 40-A pairs it with one pound of sucrose octaacetate as the bittering agent instead of denatonium benzoate. SDA 40-B is far more common in current personal care manufacturing.
Does the denatonium benzoate make the finished product taste bitter?
At the levels used, it is present to make the raw alcohol undrinkable, not to flavor your product. In a leave-on or rinse-off topical it is not a sensory factor. It is still a genuine bitterant, so keep it out of anything intended to reach the mouth.
How is SDA 40-B shipped and stored?
It ships as a flammable liquid in drums, IBC totes and bulk tankers. Store it in a cool, grounded, well-ventilated area away from ignition sources, and keep containers closed since ethyl alcohol readily picks up atmospheric moisture.
Need SDA 40-B for a fragrance or personal care program? Request a quote for bulk ethanol or reach our team through the Pristine Alcohol contact page and we will match the formula, proof and package to your specification.