What Is a Degreaser and How Does It Work?
A degreaser is a cleaner designed to strip grease films from industrial or household surfaces. There are two fundamental approaches: the alkaline route (saponifies and lifts grease) and the solvent route (dissolves grease). Most modern formulas balance both.
Scenting a degreaser is quite different from creating a fine-fragrance product. The goal is not a pleasant olfactory signature; it is to mask the sharp chemical odour of an aggressive base and give the user a sense of "cleanliness." For this reason, usage levels are low (0.2–0.6 %), and material selection is driven by scent stability. High alkalinity degrades many aroma chemicals — choosing the right molecule is what makes or breaks the formula.
Base Formula and Raw Material Table
The table below is for a water-based, predominantly alkaline general-purpose degreaser. This is a starting skeleton; adjust the alkaline level according to surface type and grease load.
| Raw Material | CAS No | % | Per 100 mL |
|---|---|---|---|
| Deionised water | 7732-18-5 | 74.4 % | 74.4 mL |
| Sodium metasilicate (alkaline component) | — | 10 % | 10 mL |
| SLES (sodium laureth sulphate) | 9004-82-4 | 6 % | 6 mL |
| Cocamidopropyl betaine | 61789-40-0 | 4 % | 4 mL |
| Propylene glycol (MPG) | 57-55-6 | 3 % | 3 mL |
| Fatty acid salt / fatty alcohol ethoxylate (surfactant) | — | 2 % | 2 mL |
| Preservative | — | 0.2 % | 0.2 mL |
| Fragrance oil | — | 0.4 % | 0.4 mL |
If you want a solvent-heavy variant, reduce the alkaline portion and introduce solvents such as d-Limonene (CAS 5989-27-5) or glycol ethers. Bear in mind that d-Limonene is itself a powerful aroma material and its citrus scent will interact with your chosen fragrance — factor this into your scenting decisions.
Preparation Steps and Fragrance Stability
Sequence is critical here. Build the alkaline base first; add the fragrance last. Introducing a fragrance oil into a hot or highly alkaline phase will both volatilise the scent and chemically degrade it.
- Prepare the water phase
Add deionised water to the vessel. Slowly add the sodium metasilicate with stirring. Alkaline powders can release heat on contact with water; allow the mixture to return to room temperature before proceeding.
- Add the surfactants
Incorporate SLES and cocamidopropyl betaine at low shear, avoiding excessive agitation. Over-mixing generates persistent foam that is difficult to disperse.
- Add the solvent and humectant
Add propylene glycol (MPG). In this formula MPG acts as a carrier solvent to help disperse the fragrance oil in the water phase — it is not a fixative. At high levels (2 %+) it can leave a tacky film on surfaces.
- pH and clarity check
The mixture should be clear and homogeneous. Cloudiness indicates incomplete surfactant dispersion; continue stirring gently until resolved.
- Scenting (final step)
Add the fragrance oil at room temperature, as the very last step. Do not pour it in neat; first prepare a premix of the fragrance with a small amount of MPG or surfactant, then blend this premix into the main batch. This ensures the fragrance oil droplets disperse evenly.
- Resting/maturation
Allow the batch to rest at room temperature (~15–20 °C) in the dark for 24–48 hours. This lets the fragrance reach equilibrium with the base. Cooler temperatures slow down this process.
- Stability testing
Place one sample in a 40 °C oven for several days and keep another at ambient conditions. Compare colour, scent, and clarity between the two. If the fragrance oil is incompatible, the scent will "drift" or turn sharp over time.
Safety, IFRA and Labelling
A degreaser is a chemically aggressive product. The risk profile must be clearly understood both during manufacturing and for the end user.
Alkalinity hazard: High-pH ingredients such as sodium metasilicate cause irritation and burns to skin and eyes. Always wear gloves and safety goggles (PPE) during production and ensure adequate ventilation.
Flammability: If the solvent-heavy variant contains glycol ethers and d-Limonene, these may be flammable (low flash point). Keep away from static electricity sources and open flames.
IFRA: This is a rinse-off or leave-on ambient product; it is not designed for application to skin. Nevertheless, IFRA limits apply to individual ingredients within the fragrance oil and depend on product category — never generalise with statements such as "any fragrance oil up to 0.5 % is safe." Cross-reference the IFRA compliance statement for your fragrance oil against your product category (typically Category 10 — household cleaning products).
Troubleshooting, Tips and FAQs
The most common problems in degreasers are scent loss, haze, and colour change. The table below provides a practical roadmap.
| Symptom | Likely Cause | Solution |
|---|---|---|
| Cloudiness / louching | Fragrance oil / solvent has not dissolved in the water phase; hydrophobic droplets are settling | Premix the fragrance oil with MPG first; slightly increase the surfactant level; switch to a more water-soluble fragrance oil rather than a heavily oily or woody type |
| Phase separation (oil film on top) | Fragrance oil usage level exceeds surfactant capacity | Keep the fragrance oil below 0.6 %; increase surfactant level or add a solubiliser |
| Scent disappears within 1–2 days | High alkaline pH is degrading the aroma materials | Select pH-stable aroma chemicals; add the fragrance last in the cold phase; review the alkaline content of the formula |
| Yellowing / colour shift | Citrus essential oils or certain aldehydes are oxidising in the alkaline environment | Add an antioxidant (BHT, CAS 128-37-0, or tocopherol); protect from light; reduce the citrus load |
| Sediment at the bottom of the bottle | Waxy or heavy insoluble components have settled out | Apply cold filtration after chilling (~0–4 °C, 24 hours), then fill into final containers |
| Excessive foam / product won't spray | Surfactant excess or viscosity too high | Reduce surfactant level; fine-tune viscosity with salt (NaCl, 7647-14-5) if needed |
Tips: When selecting a fragrance oil, test 3–5 candidates in small batches directly in the product base and compare them after ageing at 40 °C. If cost is a constraint, invest in the right molecule rather than simply increasing the usage level — a low level of a stable scent will always outperform a high level of one that degrades. When the top notes have evaporated, the base takes over; in a degreaser, that base should ideally be a musky or woody trail.
Can I use an alcohol-based perfume concentrate instead of a fragrance oil in a degreaser?
Will adding more water clear up the cloudiness?
Can I use this degreaser on my skin to remove grease?
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