The Science Behind Personal Care Oils: How Refining Impacts Quality

What Defines a High-Quality Skin Care Oil?

Plant oils are foundational ingredients in skin care, hair care and body care, but their quality depends on far more than the plant name on the label. Raw-material origin, crop and cultivar, extraction method, processing history, age, storage and exposure to light, heat and oxygen can all influence an oil’s composition, aroma, color and stability.

Each oil, including Red Raspberry Seed Oil, has its own fatty-acid profile and smaller oil-soluble constituents. Depending on the oil, these may include tocopherols, tocotrienols, carotenoids, phytosterols, squalene and phenolic compounds. Labels such as “organic,” “cold-pressed,” “unrefined” and “pure” are useful, but they cannot replace transparent sourcing, a clearly described process, appropriate testing and direct knowledge of when and how the oil was made.

This article examines how refining changes carrier oils, why large supply chains rely on standardization and what buyers gain by working directly with a producer. For a detailed composition comparison, see Raspberry and Cranberry Seed Oil Benefits for Skin.

Last updated August 21, 2026: Expanded with additional information on winterization, refining methods, oil freshness, traceability and Berry Beautiful’s in-house production process.

Refining Oils: The Process, Trade-Offs and Nutritional Impact

Refining oils involves processes such as winterizing, bleaching, deodorizing and degumming, which aim to enhance clarity, odor and shelf stability while removing impurities. These techniques address practical concerns by targeting free fatty acids, phospholipids, waxes, peroxides, aldehydes and ketones; compounds that can cause undesirable flavors, odors and inconsistencies in appearance. For industries requiring uniformity across batches, such as mass-market cosmetics, pharmaceuticals and large-scale food manufacturing, refining is a common process to meet batch-to-batch quality specifications. However, achieving this consistency can come at the expense of part of the oil's naturally occurring minor constituent profile.

Heat is integral to several major refining steps, especially bleaching and deodorization, but not every refining process is high heat. Bleaching commonly combines warm or hot oil with adsorbent materials such as bentonite or activated bleaching earth. Deodorization generally uses much higher temperatures under vacuum. The effect on tocopherols, carotenoids, phenolic compounds, squalene and phytosterols depends on the oil, temperature, time, oxygen exposure and the complete refining sequence. These compounds may be removed, reduced, transformed or concentrated into refining byproducts rather than simply “destroyed” in one uniform way.

Under some high-temperature conditions used in edible-oil refining, researchers have also documented the formation of trans isomers, glycidyl esters, 3-MCPD esters and polymeric triacylglycerols. These concerns are process specific and are most directly relevant to oils intended for consumption. They should not be used to imply that every refined cosmetic oil contains the same compounds or presents the same risk. They do, however, demonstrate how substantially an oil can be changed by intensive processing.

Oils including soybean, rapeseed, palm, corn and sunflower are often refined at industrial scale to meet food, cosmetic or technical specifications. Refining may be necessary or beneficial for a particular application, starting material or safety requirement. It is also used to create neutral color and odor, improve clarity and extend shelf life for oils that must travel through long global supply chains. All of those are practical benefits. The trade-off is that the finished oil may no longer carry the same sensory character or complete minor constituent profile as its fresh virgin counterpart.

Key Effects of Refining

• Loss of Tocopherols: Tocopherols and tocotrienols contribute to an oil’s oxidative behavior. The American Oil Chemists’ Society notes that excessively long or hot deodorization can distill away approximately 20–40% of natural tocopherols, although actual losses vary by process (AOCS Oil Refining).
• Reduction in Carotenoids: Carotenoid pigments are sensitive to processing and can be substantially reduced during bleaching and deodorization. Some carotenoids are provitamin A compounds, but not every carotenoid has provitamin A activity (Beta-Carotene Study).
• Phenolic Compound Depletion: Depending on the oil and refining sequence, phenolic compounds may be reduced or removed, changing the oil’s antioxidant capacity and chemical signature (Vegetable Oils: Effects of Processing, Storage and Use on Nutritional Value).
• Changes in Highly Unsaturated Oils: High-temperature deodorization can produce geometrical and positional fatty-acid isomers and other changes. The extent depends heavily on temperature and residence time (High-Oleic Safflower Oil Study).
• Removal of Other Minor Constituents: Degumming intentionally removes phospholipids, while bleaching and deodorization may also reduce phytosterols, squalene, pigments, volatile compounds and other unsaponifiable constituents.
• Formation of Process-Related Compounds: Intensive edible-oil refining can contribute to trans isomers, glycidyl esters, 3-MCPD esters and polymeric triacylglycerols under certain conditions (The Scientific World Journal).

It’s also worth noting that an oil may remain USDA Certified Organic while undergoing approved processing. USDA regulates organic claims for agricultural products through the National Organic Program, and qualifying cosmetics and personal care products made with agricultural ingredients may be certified when their production, handling, processing and labeling meet NOP requirements. Bentonite is included among the nonsynthetic substances allowed under 7 CFR § 205.605(a). Organic certification is meaningful, but it does not by itself mean that an oil is virgin, unrefined, recently pressed or free from heat exposure.

Variability in Refining: Light, Heavy and Low-Temperature Processing

Not all oils are refined to the same extent. Depending on how the oil is extracted - mechanically (pressed) or chemically (solvent extraction) - and the desired results, the refining process can differ significantly in intensity and impact on the oil’s properties. While terms like "light refining" and "heavy refining" are generalizations rather than technical classifications, they help convey the spectrum of refining methods, process aids and technologies commonly employed.

• Settling and Mechanical Filtration: These steps remove suspended seed solids without intentionally removing the oil’s dissolved pigments, waxes or volatile compounds. This is how Berry Beautiful clarifies its oils after pressing. Settling and filtration should not be treated as equivalent to bleaching or deodorization.
• Light Refining: This general term often describes limited treatment intended to reduce sediment, color, odor or oxidation products. Bentonite or another adsorbent may be used, frequently with oil heated around the temperatures required for effective bleaching. A reduced peroxide value after refining indicates that primary oxidation products were removed or decomposed; it does not, by itself, prove that the starting oil was fresh or that no secondary oxidation products remain.
  
• Winterization or Dewaxing: The oil is gradually cooled so waxes or other high-melting lipids crystallize and can be filtered or centrifuged out. Winterization is not a high-heat deodorization step, but it is still a form of refining and standardization because part of the oil’s natural composition is intentionally removed. The result is an oil that stays clearer at cool temperatures and appears more consistent to formulators and consumers.
• Heavy Refining: This process involves more intensive and multi-stage treatments, often incorporating degumming, alkali neutralization, bleaching agents and deodorization. These steps are designed to remove impurities, stabilize the oil and ensure consistent color, odor and extended shelf life. Deodorization commonly uses temperatures above 200°C (392°F). Solvent-extracted oils are also likely to require additional processing to remove residual solvent and meet the desired quality specification.
  

For consumers and formulators seeking an oil with its natural color, aroma and native minor constituents intact, fresh, unrefined, cold-pressed oils remain the gold standard. These oils are mechanically extracted without solvents and bypass degumming, bleaching, deodorization and winterization. They retain the character of the crop and process rather than being standardized into a neutral commodity ingredient.

Freshness, Shelf Life and the Cost of Standardization

Shelf life is a major reason oils are refined. A neutral, standardized oil is easier to transport around the world, hold in multiple warehouses and transfer between manufacturers, distributors, repackers and brands. Refining can make an oil more tolerant of a long commercial journey by removing aroma, pigments, waxes, free fatty acids and other components that may change over time or vary between crops.

That convenience has value, but it also means the buyer may receive an oil that looks and smells consistent precisely because much of its original character has been removed. Red raspberry seed oil, like rosehip seed oil and other highly unsaturated oils, can develop an increasingly strong or unpleasant aroma as it ages or oxidizes. Deodorization and other standardizing steps can make older or strongly aromatic oil easier to market, while also making it more difficult for the buyer to judge its original age and condition through sensory evaluation.

Berry Beautiful takes a different approach. We produce multiple batches throughout the year instead of relying on one large imported or commodity shipment. Our oils are commonly shipped within days to roughly three months of pressing. We can offer fresh virgin oil because we control the work ourselves: drying and cleaning the seed, mechanically cold pressing below 120°F, allowing the oil to settle, filtering it through cellulose plates, and bottling and shipping it from our Vashon Island facility.

For us, virgin and unrefined are not vague marketing terms. They describe what we do not remove and the steps we do not use. Our oils are not solvent extracted, degummed, bleached, deodorized or winterized. Natural variation in color and aroma remains part of the oil because those characteristics are part of a real agricultural product, not a defect that must always be engineered away.

Below is a diagram illustrating how oils are typically refined:

Diagram outlining the chemical and physical refining process for carrier oils extracted through mechanical pressing or solvent extraction. Winterization or dewaxing may be added when manufacturers want the finished oil to remain clear at cooler temperatures.

Source: Adapted from Gharby, S. (2022). Refining Vegetable Oils: Chemical and Physical Refining. The Scientific World Journal, 6627013. https://doi.org/10.1155/2022/6627013.

The Pitfalls of Mass-Produced Oils: Mislabeling and Nutrient Loss

Purchasing oils for skincare, hair care and other personal care products from large online platforms, resellers, white-label brands or grocery stores often comes with compromises in transparency. Issues such as adulteration, dilution, oxidation and mislabeling are well documented in high-value oil categories. A 2023 UC Davis study examined 36 private-label avocado oils and found that only 31% were pure avocado oil and only 36% met the advertised quality. Put another way, nearly 70% of the tested private-label products had a purity problem. This was an avocado-oil study, not a study of every carrier oil, but it clearly demonstrates what can happen when high-value oils move through opaque supply chains.

The concern is not limited to one oil category. Popular personal care oils, including raspberry seed oil, olive oil, rosehip oil, argan oil, grapeseed oil, jojoba oil, coconut oil, sunflower oil and almond oil can also be mislabeled, diluted, old or processed more extensively than the customer realizes. Labels boasting claims such as "Cold-Pressed," "Unrefined" or "100% Pure" suggest high-quality, minimally processed products, yet the practical meaning of these terms is often difficult for a buyer to verify without a detailed process description and traceable producer.

The term "Organic" adds another layer. USDA does not define organic as a general cosmetic-performance term, but agricultural ingredients and qualifying cosmetic or personal care products may be certified under the National Organic Program when they meet its production, handling, processing and labeling standards. USDA certification provides meaningful oversight of qualifying organic claims, but it does not guarantee that the oil was recently pressed or left unrefined.

This distinction is critical: not all Certified Organic oils are created equal, just as not all oils are created equal. Just because an oil is "Certified Organic" doesn't mean that it wasn't exposed to high heat or other refining steps in its production.

Understanding these nuances equips consumers to make more informed choices. Transparent labeling, combined with provenance and traceability, serves as a reliable indicator of a producer's commitment to quality over marketing jargon.

A long supply chain also creates an age problem that may not appear on an ingredient label. Oil can be stored by a processor, exported, held by an importer, sold to a distributor, repacked and then held again by a brand before it reaches the final customer. A current certificate of analysis may describe the tested lot, but it does not always tell the customer how recently the oil was pressed or how many storage environments it experienced along the way.

Artisanal Producers: Intimate Knowledge Builds Trust

Fresh red raspberry seed oil flowing from our press on Vashon Island, Washington.

Large ingredient distributors and mass-market suppliers often rely on paperwork, certifications and lab results to vouch for an oil’s quality, sometimes without opening, inspecting or testing every oil before repackaging and reselling it. While these documents are valuable and necessary for commerce, they cannot replace the direct, firsthand knowledge that comes from being deeply involved in every stage of production. Understanding how a virgin oil should look, smell and feel, and pairing that experience with fatty acid analysis, peroxide value, acid value and other appropriate testing, gives a producer a much stronger basis for evaluating whether an oil matches the quality implied by labels such as "Cold-Pressed," "Unrefined" or "100% Pure."

Even in an era dominated by large-scale industrial oil production, organoleptic evaluation (the sensory assessment of an oil's taste, appearance, aroma and texture) remains one of the most valuable first-line indicators of identity and condition. Sensory evaluation cannot prove authenticity on its own, but when paired with modern analytical tools it can reveal inconsistencies that paperwork alone might miss.

Over more than a decade of producing Red Raspberry Seed Oil, we’ve encountered oils marketed as "Raw, Cold-Pressed, Unrefined Raspberry Seed Oil" with colors ranging from clear to pale yellow or even pink. Color alone is not proof of adulteration because cultivar, crop, extraction and storage can all affect appearance. However, colors and aromas that fall well outside the range we know from fresh production are warning signs that warrant questions about processing, age or added color. In samples we have reviewed, third-party micronutrient and fatty acid analyses have also revealed profiles that differ significantly from what we observe in our own production. These products remain prevalent in the market, making it challenging for consumers to accurately assess quality from the label alone.

Take olive oil, for instance. If you’ve ever tasted authentic virgin, cold-pressed olive oil from regions like Spain, Greece or California, you’ve likely noticed its bold, spicy flavor and nuanced notes - qualities that are stripped away in the refined, mass-market versions commonly found on grocery store shelves. Even among raw, unrefined oils, subtle variations exist due to factors like growing regions, olive varieties and production methods, all contributing to distinct flavor profiles and characteristics.

The same principle applies to personal care oils like Red Raspberry Seed Oil and Cranberry Seed Oil. Without firsthand experience of the authentic, unrefined product, it’s nearly impossible to fully appreciate the unique qualities that set it apart from heavily processed or adulterated alternatives.

As a small, artisanal producer with full oversight of our supply chain, we have an undeniable advantage: we can speak truthfully and confidently about the quality of our oil because we are involved at every stage of production. From the subtle variations in color, aroma, texture and feel to the nutrient profile (not just in every batch but even during the pressing process itself) we know our oils intimately. Years of hands-on experience have sharpened our ability to recognize nuances that others might overlook: the warm scent of freshly pressed oil, the ideal temperature of the collection pan or the clarity of the oil after filtering. This direct involvement ensures that every bottle reflects the true integrity of the oil, free from the inconsistencies and uncertainties that arise in complex, outsourced supply chains.

We also know exactly what happens between the seed and the bottle. We dry and clean the seed, mechanically cold press below 120°F, allow the oil to settle, filter it through cellulose plates, and bottle and ship it ourselves. We do not send the oil to a separate refinery, broker or repacker before it reaches our customers.

Making multiple batches throughout the year lets us offer something that a long commodity supply chain struggles to provide: fresh virgin oil with a known production date and a direct line back to the people who pressed it. See our complete berry seed oil process.

Traceability Is a Responsibility, Not a Luxury

Brands and distributors have an ethical duty to ensure that their claims about sourcing, production and processing are truthful and verifiable. This goes beyond liability and compliance; it’s about respecting the trust of customers who rely on these products for health and wellness.

Managing and distributing many different oils, sourced from many different producers, presents an enormous challenge for companies. Ensuring consistent quality across a diverse product range requires staff to possess detailed knowledge of each oil’s unique characteristics. Unfortunately, in practice, many such operations lack this expertise.

At its core, traceability isn’t just about paperwork or locality, it’s about firsthand knowledge of all the steps of production - which allows one to personally vouch for the product’s integrity. Producers who are intimately involved in their craft can look a customer in the eye and assure them, with confidence, that every bottle represents genuine quality, transparency and care.

By choosing to support producers who prioritize integrity and craftsmanship over standardization and mass appeal, buyers are not only investing in superior oils but also helping to create a marketplace where authenticity and accountability set the standard, not the exception.

Retail and Bulk Oil Options

For personal use and small formulations, explore our virgin Red Raspberry Seed Oil, Certified Organic Red Raspberry Seed Oil and Cranberry Seed Oil.

For brands, formulators and manufacturers, purchase Bulk Red Raspberry Seed Oil, review our complete bulk berry seed ingredient options, or learn how we work with bulk ingredient buyers. We also offer custom botanical oil infusions made with our own red raspberry seed oil.

Sources and References

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• Oil Refining – American Oil Chemists’ Society
  • Explains degumming, neutralization, bleaching, winterization and deodorization, including the compounds removed and the effect of overly long or hot deodorization on natural tocopherols.
• Sunflower Oil Winterization Using Cellulose-Based Filtration – Open-access research
  • Describes how waxes crystallize during cooling and are removed through filtration during winterization.
• Chromatographic Evaluation of Tocols and Sterols of Processed Canola Oil and Deodorizer Distillate
  • Documents how valuable tocols and sterols can move into deodorizer distillate during refining.
• Effects of Refining Process on Sunflower Oil Minor Components – OCL
  • Reviews the effects of individual refining stages on tocopherols, phytosterols and other minor constituents.
• Micronutrients in Vegetable Oils: Impact of Crushing and Refining Processes on Vitamins and Antioxidants – ResearchGate
  • Examines nutrient losses in sunflower, rapeseed and soybean oils during crushing and refining, highlighting reductions in tocopherols, sterols and polyphenols.
• Effects of Refining Processes on the Physicochemical Properties of Some Selected Vegetable Oils – Journal of Chemical Sciences
  • Explores the chemical and physical changes in palm, palm kernel and soybean oils post-refining, including reductions in peroxide and acid values.
• Supercritical CO2 Degumming and Physical Refining of Soybean Oil – Academia.edu
  • Analyzes SC-CO₂ degumming for reducing phosphorus and iron content, improving oil clarity and enhancing oxidative stability.
• Refining of High Oleic Safflower Oil: Effect on Sterols and Tocopherols – ResearchGate
  • Examines nutrient losses, including sterols and tocopherols, during the degumming, bleaching and deodorization of safflower oil.
• Physical Refining of Sunflower Oil – Academia.edu
  • Explores the advantages of physical refining over chemical refining, focusing on economic benefits, environmental impact and improved processing technologies.
• Effects of Seed Roasting on Tocopherols, Carotenoids and Oxidation in Mustard Seed Oil During Heating – ResearchGate
  • Examines the effects of roasting mustard seeds on oil quality, showing improved oxidative stability, preserved tocopherols and enhanced carotenoid content.
• Vegetable Oils: Effects of Processing, Storage and Use on Nutritional Value – SpringerLink
  • Discusses how refining, storage and cooking processes impact the nutritional composition and oxidative stability of vegetable oils.
• Refining Vegetable Oils: Chemical and Physical Refining – PMC
  • Compares chemical and physical refining, detailing nutrient loss and formation of unwanted by-products like 3-MCPD esters.
• Edible Oil Refining: Current and Future Technologies – Wiley Online Library
  • Explores innovative technologies in oil refining, including enzymatic degumming, nanoneutralization and sustainability-focused processes.
• Ecological-Safe and Low-Cost Activated Bleaching Earth – ScienceDirect
  • Evaluates thermal activation methods for environmentally friendly bleaching earth and their impact on oil quality.
• Minor Constituents in Canola Oil Processed by Traditional and Minimal Refining Methods – ResearchGate
  • Compares traditional and minimal refining techniques, highlighting nutrient retention benefits and quality improvements in canola oil.
• Phytosterols in edible oil: Distribution, analysis and variation during processing – ScienceDirect
  • This study highlights the impact of oil refining on phytosterol content, emphasizing the need for improved methods to minimize nutrient loss and preserve quality in edible oils. Enhanced analytical techniques and further research into degradation mechanisms are critical to maximizing the health benefits of phytosterols.
• 7 CFR § 205.605: National List of Allowed Nonagricultural Substances – Electronic Code of Federal Regulations
  • Provides the current regulatory listing for substances including bentonite in qualifying processed organic products.
• National Organic Program (65 FR 80548) – Federal Register
  • Outlines USDA regulations for organic certification, including standards for oil refining processes.
• National Organic Program Correction (66 FR 15619) – Federal Register
  • Provides corrections and clarifications to the National Organic Program regulations.
• USDA Organic Regulations on Cosmetics and Personal Care – USDA
  • Clarifies labeling standards for organic cosmetics, personal care and body care products under USDA guidelines.
• UC Davis Article on Avocado Oil Adulteration – UC Davis
  • Highlights findings on avocado oil adulteration, rancidity and mislabeling in retail products.
• 2023 Study: Quality and Purity of Private Label Avocado Oil – Food Control
  • Revealed that 70% of private-label avocado oil samples were rancid or adulterated, emphasizing ongoing quality control issues.