5 min read

Flash Points: What They Mean for Formulators

Written By: Robin Lander

You may have come across the term flash point when working with essential oils and wondered what it really means. Technically a safety specification, flash points are used to classify materials like essential oils for handling and transport, but they can also influence how you choose to formulate with them.

Being aware of flash points is especially helpful when making aromatic products that involve heat during production or use such as candles, soap, and some cosmetics. In this article, we will explain what flash points are, where to find them, and how they may impact your formulations – including a handy, downloadable reference guide.

Understanding Flash Points

Each essential oil has a specific flash point – the temperature at which its vapors can ignite if exposed to an open flame or spark. In general, the lower the flash point, the more volatile and combustible the oil.

Because essential oils are composed of volatile aromatic molecules, they begin to evaporate the moment they are exposed to air. If they are heated, this evaporation accelerates. The flash point is a key safety guideline, indicating the point at which extra care is needed to prevent ignition.

If essential oils are exposed to excessive or prolonged heat, especially at or near their flash point, the lighter aromatic molecules may degrade or evaporate rapidly, altering the oil’s aroma and overall intensity.

Ideally, you won’t be exposing your essential oils to heat. However, when heat is unavoidable, understanding flash points can help you optimize your formulations, minimize aroma loss, and preserve the integrity of your formula.

Where to Find Flash Points

The flash point of each oil can be found in Section 5 of the Safety Data Sheet (SDS), viewable in the Documentation drop-down menu located on the left side of the product page.

For convenience, we’ve also created a downloadable document listing the flash points of all our essential oils:

Click Here for the Flash Point Reference Guide

Flash Points and Candle Crafting

When using essential oils to scent candles, flash points offer insight into how quickly an oil’s aroma may evaporate when exposed to heat as well as how it may perform in terms of fragrance ‘throw.’ For context, the melted candle wax in a burning candle, called the melt pool, is crucial for fragrance throw and typically ranges in temperature from 120°F to 185°F depending on wax type and wick size.

Let’s consider a candle fragrance formula made with Grapefruit, Ruby Red, Ylang Ylang III - Organic, and Patchouli - Double Distilled:

·         Grapefruit, Ruby Red is a bright citrus top note with a low flashpoint of 111.2°F. While it adds an immediate burst of freshness, its aroma dissipates quickly when heated, resulting in lighter throw. For better performance, a citrus like Bergamot - Organic with a flashpoint of 136.4°F may offer more throw.

·         Ylang Ylang III - Organic is an intensely floral middle/top note with a flash point of 199.4°F. Higher flashpoints generally translate to better candle performance. However, floral oils still contain delicate aromatic compounds that can degrade under prolonged or excessive heat. With floral oils, careful temperature control during production is key.

·         Patchouli – Double Distilled is a more viscous base note with a high flashpoint of 238.1°F. Its low volatility allows it to evaporate slowly, contributing to a stronger, longer-lasting scent throw.

Pro Tip: When formulating for candles, keep flash points in mind and be sure to include top, middle, and base notes in your blend. Not only will this give you a more balanced, well-rounded aroma, but the higher flash point base notes can also act as fixatives to help slow the evaporation of more volatile top notes.

For more information on using essential oils in candles, please see our article In the Light: Essential Oils and Candle Crafting

To learn more about formulating aromatic compositions with base, middle, and top notes, see our article Natural Perfumery Basics

For Soap and Cosmetic Formulation

The same principles apply when creating soap and cosmetics that require heat in their production. Whenever possible, add essential oils at the lowest temperature of your production process and avoid reheating once they’re incorporated.

If warming is unavoidable after essential oils have been added, try to keep temperatures below the lowest flash point oil in your formula (ideally <104°F and no greater than 140°F) and limit heat exposure to the shortest time possible.

For Shipping Classification

Oils with low flash points, such as many citrus oils and some conifer tree oils, are categorized as Class 3 – Flammable. We must follow strict transportation regulations for these oils and they may require special handling or incur added fees when shipped by air, depending on bottle size and total quantity of the order.

For more details about how we ship according to Hazmat regulations, please see our article Hazmat Shipping 101. 

If Your Shipment Gets Hot in Summer

While we package orders carefully, extreme summer temperatures can warm bottles in transit. Most essential oils have flash points well above 100°F, but if an oil reaches or exceeds its flash point, do not open the bottle while it’s hot.

Allow the oil to cool fully to room temperature before opening. As it cools, vaporized aromatic compounds will condense back into the liquid, helping preserve the oil’s aroma profile.

The good news is that short periods of heat during transit are not an issue for most aromatic materials. For more information about how heat affects your products, see our article Stay Cool: Tips to Keeping Your Oils Safe When Temperatures Soar

Final Thoughts for Formulators

More than a safety specification, flash points offer practical data for how an essential oil will behave under heat, allowing you to make informed choices regarding formulation and production. Knowing an oil’s flash point will help you anticipate potential changes in aroma, evaporation, and overall performance when oils are exposed to elevated temperatures.

Have more questions about flash points? Contact us and we are happy to help!