Why is CWS four times more antioxidative than HWS?

Production, active compound concentration, and solubility of Rooibos extracts

There are two types of Rooibos extracts: hot water soluble (HWS) and cold water soluble (CWS). Both are made from the same high-quality leaves of the Rooibos plant – yet they differ significantly in their application, antioxidant capacity (ORAC value), and technological production.

This article clearly explains the differences, why CWS has a significantly higher antioxidant effect – and how this relates to fractionation, solubility, and stabilization.

1. Raw material: identical – but processed differently

Both HWS and CWS are based on the same plant source: *Aspalathus linearis*, better known as Rooibos. The fine, needle-like leaves naturally contain a variety of polyphenols, flavonoids, and other antioxidants.

What determines the quality of the extract is how these active compounds are extracted and stabilized in the final product. And this is where the difference begins.

2. The classic HWS extract: for warm applications

In the hot water soluble Rooibos extract (HWS), the dried Rooibos leaves are first extracted with hot water. The antioxidant compounds dissolve, the tea is then filtered, and finally processed into powder through spray-drying.

This method preserves the classic Rooibos flavor and is ideal for teas and creams. Since no additional processing steps like fractionation or stabilization are required, the full range of natural compounds is retained – though in lower concentration compared to CWS.

Complete solubility occurs only at temperatures of around 80 °C or higher – because the extract is processed without carrier or auxiliary substances.

3. The modern CWS extract: high efficacy at room temperature

The CWS extract is also hot-extracted – but this is followed by selective fractionation, in which the antioxidant fractions are specifically enriched. Undesired or less effective plant components are removed, while the polyphenols and flavonoids remain concentrated.

In addition, these sensitive compounds are protected from oxidation through natural stabilization processes. As a result, the high antioxidant activity remains stable in the powder over the long term – even without additives such as maltodextrin.

The result is a highly concentrated Rooibos extract with an ORAC value of ≥ 4000 µmol TE/g – about four times higher than HWS. It is fully soluble at room temperature.

4. What does “selective fractionation” mean?

Fractionation refers to separating a plant extract into its individual components. In selective fractionation, those substances with particularly strong antioxidant effects—such as specific flavonoids or phenolic compounds—are deliberately isolated.

This does not mean that other substances are artificially removed; instead, the natural content of the active constituents is increased. The result is an extract that can deliver a much stronger effect at the same volume.

5. Why is the ORAC value higher in CWS?

The ORAC value (“Oxygen Radical Absorbance Capacity”) measures how well a food can neutralize free radicals in the body. A higher value therefore indicates stronger antioxidant activity.

In the case of CWS, the combination of fractionation and stabilization results in a significantly higher concentration of active compounds – and thus a much higher ORAC value compared to HWS.

ORAC Values Compared

Ingredient / Extract	ORAC Value (µmol TE/g)
Rooibos Extract CWS	≥ 4000
Green Tea Extract	approx. 3800
Goji Berries (dried)	approx. 3200
Blueberries (dried)	approx. 2400
Turmeric Powder	approx. 1270
Rooibos Extract HWS	≥ 1000

Note: The ORAC value measures antioxidant capacity. The higher the value, the stronger the cellular protection.

6. Why is the CWS soluble in cold water?

Thanks to the fine processing of the CWS extract (e.g., spray-dried microparticles without additives), the powder dissolves completely at just 20 °C. No temperature increase is needed – ideal for shakes, iced teas, and sensitive cosmetic applications.

HWS, on the other hand, requires at least 80 °C to fully dissolve. This is due to the natural structure of the powder, which, without additional processing steps, needs higher thermal activation.

Conclusion: Two extracts, two applications

Both variants have their justification:

HWS is ideal for classic Rooibos teas, warm creams, or applications involving heat.
CWS is perfect for modern, cold applications with maximum antioxidant effect.

Anyone who wants not only to enjoy Rooibos but also to use it functionally opts for CWS – the modern answer to centuries-old plant power.

What about “steam extract” or “Rooibos condensate”?

In retail, you can find cheaper extracts produced from the condensate of steam sterilization or through non-specific steam treatments. While both methods deliver a Rooibos aroma, they usually contain significantly fewer antioxidants than an HWS—or especially a CWS—extract.

In brief:

🔹 Condensate from steam sterilization:
By-product of the hygienic treatment of Rooibos.
➤ Low active-compound density, low ORAC value.
🔹 Steam extraction:
Plant material is treated and extracted with steam.
➤ Gentler than hot water, but usually less selective and lower in actives.

Comparison of Extraction Methods

Method	Purpose	Quality / Special feature
1. Condensate from steam sterilization	Sterilization of finished Rooibos	Low active-compound content, by-product
2. Steam extraction	Targeted extraction with steam	Gentle, but less selective
3. HWS / CWS	Hot-water extraction & fractionation	Highest purity & antioxidant content

Conclusion:

➡️ These extracts can be aromatic – but they are not comparable in their functionality. A high ORAC value and complete water solubility at 20 °C or 80 °C are technical features that can only be achieved through targeted extraction, fractionation, and stabilization.

💬 Anyone comparing should know exactly what is being compared. Price differences in Rooibos extracts almost always have a technological background – and they affect quality, flavor, and efficacy.

What happens during selective fractionation?

Fractionation means that after the initial hot-water extraction, specific groups of compounds are selectively separated and further processed. In the case of Rooibos extract, these are primarily polyphenols and flavonoids – including aspalathin and nothofagin.

Selective fractionation specifically involves:

The Rooibos extract is separated into different fractions (e.g., by filtration, centrifugation, membrane technologies, or adsorption).
The fraction with the highest concentration of antioxidants is concentrated and further processed.
This results in a highly pure, especially antioxidant-rich extract – the final CWS.

➡️ This targeted concentration explains the four times higher ORAC value of CWS compared to HWS.

How are polyphenols enriched?

Polyphenols are water-soluble secondary plant compounds. After extraction, methods such as:

Reverse osmosis (to remove water and concentrate)
Adsorbent resins to selectively bind polyphenols and then wash them out again
Spray-drying in a controlled matrix, where the heat-sensitive actives are protected inside micro-fine droplets

The result is a dry extract with an especially high content of antioxidant substances – this forms the core of CWS.

Why does HWS dissolve only at 80 °C, while CWS dissolves already at 20 °C?

Solubility depends on the physical structure of the extract:

HWS extract often still contains complex molecular compounds (e.g., larger tannins) that only dissolve at higher temperatures.
It also has a less porous particle structure – due to spray-drying, the particles are denser and require thermal energy to fully open up.

The CWS extract, on the other hand:

Is specifically processed to have a micronized, open structure.
It contains no heat-dependent bonds and therefore dissolves quickly and completely even at room temperature – even in cold water.

What does "stabilization" mean in the context of extracts?

In this context, stabilization means:

Protecting sensitive compounds (e.g., polyphenols, flavonoids) from oxidation, light, or heat during processing.
Using gentle drying techniques, such as controlled spray-drying under nitrogen atmosphere or vacuum.
Optionally adding natural protective agents (e.g., gum arabic), if purity requirements allow – in your product, this appears to be unnecessary, which indicates especially well-controlled production.

Goal: The antioxidant effectiveness remains stable throughout the entire product lifecycle – from production to end use by the customer.