Introduction: does it really matter how juice is made?

Walk into any supermarket and you'll find shelves lined with juice. Browse a brand like Sage Green and the language shifts — "cold-pressed," "organic," "gently pasteurized." It sounds like marketing. But there's genuine science behind these terms, and understanding what they actually mean gives you a much clearer picture of what you're drinking — and why the process behind your juice matters as much as the ingredients in it.

Most people choose juice based on what's on the label: the fruit, the claimed vitamins, the word "natural." Very few think about what happened to the juice between the farm and the bottle. That's the gap this article fills.

Whether you're new to functional juicing or you've been exploring the world of cold-pressed drinks for a while, this guide will give you the science, the history, and the practical knowledge to make better choices for your health.

If you're new to Sage Green and not sure where to start, read our beginner's guide to our juice range first — it walks you through our Functional Juices and EveryDay Organic range and helps you find the right starting point.

A brief history: from ancient remedies to the cold-press revolution

Humans have been extracting juice from plants for thousands of years. Ancient Egyptians used stone presses to extract juice from pomegranates and figs, and early Greek physicians including Hippocrates prescribed fruit and vegetable preparations for digestive ailments and wound healing. In medieval Europe, monasteries maintained herb gardens and produced pressed botanical remedies for everything from fever to liver complaints — many of the same plants, including nettle, rosehip, and sea buckthorn, that Sage Green uses today.

The industrial transformation of juice began in the late 19th century. In 1869, American dentist Thomas Bramwell Welch developed the first commercially bottled grape juice using a rudimentary pasteurization method he adapted from Louis Pasteur's earlier work on wine and milk. His goal was to produce an unfermented communion wine — he succeeded, and effectively invented the modern juice industry in the process.

For the next century, heat pasteurization became the universal standard for commercial juice production. It was safe, scalable, and allowed juice to travel vast distances without spoiling. The nutritional cost was understood by food scientists but largely invisible to consumers.

The cold-press movement emerged in the 1930s when Dr. Norman Walker, a British-born health advocate, developed one of the earliest hydraulic juice presses — the Norwalk Juicer — in California. Walker was obsessed with the idea that heat destroyed the living properties of fruit and vegetables, and he was not entirely wrong. He lived to 99 and attributed much of his longevity to raw juice. His ideas were considered eccentric at the time. By the 2010s, cold-pressed juice had become a multi-billion euro global industry.

Today, the conversation has matured beyond "raw vs heated." The science is more nuanced, the processing methods more varied, and the best producers — Sage Green among them — are thinking carefully about how to get maximum nutritional benefit to the consumer in a product that is also safe and reliable.

📸 Image suggestion: A split-image or side-by-side: one side showing dark, richly coloured cold-pressed juice in a glass bottle; the other showing a pale, commercially packaged juice carton. Visual contrast tells the story without words.

What is cold-pressing? The science of pressure over heat

Cold-pressing uses hydraulic pressure — not heat — to extract juice from fruits and vegetables. The produce is first crushed into a pulp, then pressed under thousands of kilograms of force, squeezing out the liquid without generating significant heat in the process.

Because no heat is applied during extraction, vitamins, enzymes, minerals, and delicate phytonutrients remain in their most intact form. The cell walls of the fruit or vegetable are broken down mechanically, releasing their contents without the chemical reactions triggered by heat.

This is why cold-pressing is the starting point for everything we make at Sage Green. The ingredients we work with — aronia, sea buckthorn, rosehip, beetroot, black radish, pomegranate, nettle, ginger, turmeric, and others — are chosen specifically for their documented nutritional profiles. Cold-pressing is the only extraction method that respects those profiles from harvest through to bottle.

The shorter shelf life of cold-pressed juice is a direct consequence of this minimal processing. Without heat to sterilise it, it must be refrigerated and consumed relatively quickly. We consider this a sign of integrity, not a limitation.

Want to understand more about the specific ingredients in our range and what they do? Explore our ingredient articles — we've written in depth about aronia, rosehip, black radish, sea buckthorn, and more.

Not all pasteurization is the same — this is where it gets important

Most discussions about pasteurization treat it as a single thing. It isn't. It exists on a wide spectrum, and the method used makes an enormous difference to what survives in the final juice.

Standard high-heat pasteurization

Used widely in mass-market juice production, this involves heating juice to temperatures between 70°C and 100°C. For shelf-stable carton products, sterilization processes can reach 138°C for ultra-high temperature (UHT) treatment. At these temperatures, harmful bacteria are eliminated — but so is a significant portion of the juice's nutritional content.

Vitamin C is the most vulnerable nutrient. Research published in Food Science and Technology found that pasteurization at 85°C reduced ascorbic acid content in strawberry juice by approximately 35% compared to unheated filtered juice, while more extreme sterilization processes can destroy 51–56% of vitamin C [1]. A comprehensive review of vitamin C stability across different processing methods confirmed these losses are consistently observed across a wide range of fruit and vegetable juices subjected to standard thermal treatment [2]. The losses vary by juice type — a study of watermelon juice found vitamin C became essentially undetectable after just 10 minutes at 80°C, while mango juice showed a more modest 27% reduction under the same conditions [3].

Polyphenols and anthocyanins — the plant compounds responsible for many of the most compelling health benefits associated with dark berries, beetroot, and pomegranate — are also significantly affected by high heat. This is especially relevant for aronia, one of Sage Green's core ingredients and one of the most polyphenol-dense berries in the world.

B vitamins, particularly folate (B9) and thiamine (B1), are similarly vulnerable to heat processing. Aronia berries contain vitamins B1, B2, B3, B5, B6, folic acid, as well as vitamins C, E, and K — a profile that makes careful processing genuinely important [4].

Minerals, on the other hand, are much more resilient. Potassium, calcium, and magnesium are elemental compounds that heat cannot degrade, and they survive pasteurization largely intact [5].

Gentle pasteurization — a different approach

Gentle pasteurization operates on different principles. It uses lower temperatures for carefully controlled durations — enough to ensure microbial safety and a responsible shelf life, while minimising thermal damage to heat-sensitive nutrients.

The scientific evidence strongly supports this approach. Research comparing pasteurization temperatures consistently shows that browning reactions and colour degradation in juice are significantly lower at reduced temperatures, and that anthocyanin and polyphenol retention improves meaningfully when heat intensity is reduced. A study examining aonla juice found that while polyphenol content decreased over storage time regardless of pasteurization temperature, browning — a visible indicator of heat damage — was significantly higher in juices treated at 90–95°C versus those treated at 75–80°C [6].

This is what Sage Green uses. Our juices are cold-pressed first — so the extraction stage preserves everything — and then gently pasteurized to a standard we are confident about from both a safety and nutritional perspective.

What cold-pressing and gentle pasteurization means for Sage Green's specific ingredients

This is not abstract. The ingredients Sage Green uses are chosen because their documented compounds are biologically active — and cold-pressing plus gentle pasteurization is how we protect them.

Aronia contains extraordinarily high concentrations of anthocyanins and proanthocyanidins. Research on aronia juice published in PMC demonstrated that anthocyanin degradation is strongly temperature-dependent: pigments were significantly more stable at lower processing temperatures (60°C) than at 80°C, with half-life values clearly favouring gentler treatment [7]. A separate study on Aronia melanocarpa juice confirmed that conventional high-temperature UHT sterilization caused notable browning and functional compound loss, while lower-temperature approaches preserved polyphenols and anthocyanins more effectively [8].

Rosehip and sea buckthorn are among the richest natural sources of vitamin C on the planet — rosehip can contain up to 20 times the vitamin C of oranges. Protecting this during processing is directly relevant to the functional value of these juices.

Beetroot contains betalains — nitrogen-containing pigments responsible for its distinctive deep red colour and associated with cardiovascular and anti-inflammatory benefits. Betalains are heat-sensitive, making cold extraction and minimal thermal treatment directly relevant to how much functional value survives into the bottle.

Ginger provides a useful illustration of what cold-pressing specifically preserves. Research published in Food Research International found that cold-pressed ginger juice contained 2.3 times the concentration of 6-gingerol compared to heat-extracted preparations — the compound associated with ginger's well-documented anti-inflammatory and digestive properties.

Read more about the science behind these specific ingredients in our articles section, where we've published in-depth posts on aronia, rosehip, black radish, sea buckthorn, and more.

🌿 Fun facts: things you probably didn't know about juice and pasteurization

• Louis Pasteur never worked with juice. He developed his pasteurization method in the 1860s specifically for wine and beer, after discovering that microorganisms caused fermentation and spoilage. The application to juice came decades later.
• Aronia berries have a higher antioxidant capacity than blueberries, açaí, and cranberries — a fact confirmed in multiple comparative studies. They were largely unknown outside Eastern Europe until the late 20th century, despite having been cultivated in Russia and Poland for over 100 years.
• The word "pasteurization" was coined in honour of Louis Pasteur in 1895 — 13 years after his death. He died in 1895 having received the honour of seeing his name attached to the process during his lifetime, but the formal term came posthumously.
• Sea buckthorn was used by the ancient Greeks to feed horses before battle, because they noticed it gave the animals shinier coats and more energy. The scientific name Hippophae literally means "shining horse." Today we know this is due to its extraordinary omega-7 fatty acid and vitamin C content.
• Cold-press hydraulic technology existed long before juice bars. The same hydraulic pressing principle was used for centuries to extract olive oil, press wine grapes, and process flaxseed for linseed oil. Norman Walker didn't invent hydraulic pressing — he just applied it to fruit and vegetables for drinking.
• Gentle pasteurization can sometimes increase vitamin C bioavailability. One study of strawberry juice found vitamin C content actually increased after thermal treatment, because heat stress caused cell rupture that released more ascorbic acid into the juice [9]. The science is genuinely more complex than "heat = bad."
• Rosehip has been used medicinally for over 2,000 years. Hippocrates recommended preparations made from wild rose fruits, and rosehip syrup was distributed to children across Britain during World War II as a vitamin C supplement when citrus fruits were unavailable due to wartime rationing.

The transparency problem in commercial juice

The juice industry has a labelling problem worth understanding. Terms like "100% juice," "rich in vitamin C," and "natural" are often technically accurate while obscuring what has actually happened to the product between farm and shelf.

A juice labelled "rich in vitamin C" may have had synthetic ascorbic acid added after processing to compensate for what high-heat treatment destroyed. "100% juice" tells you nothing about whether the product was concentrated and reconstituted, stored for months, or processed at 130°C. "Natural" has no regulated definition in most markets.

Understanding the difference between extraction methods and pasteurization intensities gives you the tools to read those labels more critically — to ask not just what's in this juice, but what was done to it, at what temperature, and how long ago.

At Sage Green, we think you deserve straight answers to those questions. Our juices are cold-pressed and gently pasteurized. We use organic ingredients selected for their functional properties. We do not add synthetic vitamins, concentrates, or fillers. And we are transparent about our process because we believe transparency is the foundation of trust — not a marketing strategy.

How to choose the right juice for your health goals

Now that you understand the processing side, the second part of choosing well is matching the right juice to what your body needs right now.

Our Functional Juices are formulated around specific health outcomes — immunity, energy, detox, liver support, heart health, sleep, and more. Each bottle is built around ingredients with documented benefits in those areas.

Our EveryDay Organic Juices are for daily enjoyment — clean, organic, additive-free, and suitable for the whole family including children. No strict routines required.

If you're not sure where to begin, our bundles offer curated combinations across the range — a practical way to explore multiple products and find what your body responds to best.

And if this is your first order, use code WELCOME10 for 10% off.

The bottom line

Cold-pressing preserves the nutrients in fruits and vegetables during extraction — that part is straightforward. Gentle pasteurization keeps the product safe without the aggressive heat that standard commercial processing uses, which science consistently shows degrades heat-sensitive vitamins, polyphenols, and anthocyanins.

The spectrum between a cold-pressed, gently pasteurized juice from a transparent brand and a high-heat commercially sterilized carton from a supermarket shelf is wide. The nutritional difference is real. The ingredient quality difference is real. And now you have the science to understand exactly why.

→ Browse our cold-pressed Functional Juices → Explore our EveryDay Organic Juices → Read more about our ingredients

References

1. Klopotek Y, Otto K, Böhm V. Processing strawberries to different products alters contents of vitamin C, total phenolics, total anthocyanins, and antioxidant capacity. J Agric Food Chem. 2005;53(14):5640–5646. Cited in: Wojdyło A, Oszmiański J, Bielicki P. Molecules. 2021;26(3):619. https://pmc.ncbi.nlm.nih.gov/articles/PMC7824742/
2. Wojdyło A, Oszmiański J, Bielicki P. Impact of innovative technologies on the content of vitamin C and its bioavailability from processed fruit and vegetable products. Molecules. 2021;26(3):619. https://pmc.ncbi.nlm.nih.gov/articles/PMC7824742/
3. Mandha J, Shumoy H, Matemu AO, Raes K. Characterization of fruit juices and effect of pasteurization and storage conditions on their microbial, physicochemical, and nutritional quality. Food Science and Technology. 2022. https://doi.org/10.1016/j.lwt.2022.114060
4. Jurikova T et al. Fruits of black chokeberry Aronia melanocarpa in the prevention of chronic diseases. Molecules.2017;22(6):944. https://doi.org/10.3390/molecules22060944
5. ScienceInsights. Does pasteurization kill nutrients in juice? 2025. https://scienceinsights.org/does-pasteurization-kill-nutrients-in-juice/
6. Kumar A, Chauhan GS. Effect of pasteurization temperature on quality of aonla juice during storage. J Food Sci Technol. 2013;50(3):617–621. https://pmc.ncbi.nlm.nih.gov/articles/PMC3551156/
7. Tkaczyńska A et al. Effect of grapefruit seed extract on polyphenol, anthocyanin and colour properties of aronia juice during heat treatment. Progress in Agricultural Engineering Sciences. 2025. https://doi.org/10.1556/446.2025.00169
8. Zhao X et al. Comparative study on physicochemical properties, functional components, color and anthocyanin profiles of Aronia melanocarpa juice using different sterilization methods. Food Innovation and Advances.2024;3(1). https://doi.org/10.48130/fia-0024-0008
9. Odriozola-Serrano I et al. Comparative evaluation of UV-VIS, HPLC-DAD and HPLC-MS/MS for strawberry juice vitamin C and antioxidant capacity analysis following different thermal treatments. J Food Compos Anal. 2007. Cited in: Plant Based News. Strawberry juice retains vitamins after pasteurization. 2024. https://plantbasednews.org/news/science/strawberry-juice-vitamins-pasteurization/