11/09/2026
Cold Pressed… But What Does That Actually Mean?
My Living by Design curiosity sent me down another rabbit hole and this time it was juice.
I’ve been juicing for years. I’ve used different machines, worked with different extraction methods, watched how different fruits and vegetables behave under pressure, and seen first-hand how dramatically yield, texture, colour and even taste can change depending on the equipment being used.
But recently I started questioning something I had largely taken for granted..
What does “cold pressed” actually mean?
Because the deeper I looked, the more I realised that two bottles can both carry the words cold pressed while having been produced using substantially different extraction methods.
And if the extraction is different, does that change the juice?
Its yield?
Its exposure to oxygen?
Its plant compounds?
Its vitamin content?
Its shelf life?
Suddenly, “cold pressed” didn’t feel like a particularly useful description at all.
Not all cold pressing is the same
There are several ways of mechanically extracting juice from plants.
One common system used in domestic and smaller commercial “cold press” machines is the slow masticating or auger method.
Produce enters the machine and a slowly rotating auger crushes and compresses it against a screen. Juice passes through the screen while the remaining pulp is continuously expelled.
It’s relatively slow and avoids the extremely high rotational speeds associated with traditional centrifugal juicers.
But then there is another method entirely.
This is the method used by traditional machines such as the Norwalk and commercial systems such as Goodnature.
It is a two-stage process.
First, the fruit or vegetable is ground, shredded or triturated.
Instead of immediately extracting the liquid, the machine deliberately breaks the plant material down into a wet pulp.
That pulp is then placed inside a filtering cloth or press bag.
Only then does the second stage happen:
pressure.
Significant hydraulic or pneumatic force is applied across the pulp and the liquid is physically expressed through the filter.
So although both systems may be described as “cold pressed”, mechanically they are doing very different things.
One is essentially…
produce → auger → compression through a screen → juice
The other is…
produce → cellular disruption/maceration → pulp → filter cloth → hydraulic pressure → juice
And that distinction fascinated me.
Why grind the produce first?
This is where my curiosity really kicked in.
Think about trying to squeeze liquid from a whole carrot.
Now think about finely breaking that carrot down first, creating a mass of disrupted plant tissue, wrapping that material in cloth and then applying substantial pressure evenly across the entire pulp.
They are very different extraction environments.
The grinding or trituration stage increases the disruption of the plant structure before the extraction pressure is applied.
Research into mechanical juice expression has demonstrated that the way plant tissue is disrupted before pressing can influence extraction efficiency.
That doesn’t automatically mean “more nutrients”.
But it does mean how we prepare the plant before extracting its liquid matters.
And I’ve witnessed that practically in our own production.
Changing equipment and processing techniques has produced substantial differences in the amount of liquid we can recover from the same types of produce.
That sent me into the next question.
Does one method actually produce a more nutritious juice?
This is where things become far more interesting because the answer isn’t as simple as the marketing would have us believe.
There are plenty of claims suggesting cold-pressed juice automatically contains more vitamins, enzymes, antioxidants and phytonutrients.
But when you actually start reading the research, the picture becomes much more nuanced.
Some studies comparing juice extraction methods have found higher levels of certain polyphenols, flavonoids, anthocyanins, vitamin C or antioxidant activity in slower extraction methods.
Other studies have found particular compounds to be higher following different extraction techniques.
And some have found no significant nutritional advantage at all between so-called cold-pressed and centrifugal extraction for the compounds measured.
That is important.
Because science doesn’t appear to support the blanket statement..
“Cold pressed juice is always more nutritious.”
Different plants behave differently.
Different compounds behave differently.
And different machines that researchers themselves call “cold press” may not even use the same extraction mechanism.
And there’s the terminology problem
This was perhaps the most surprising part of my research.
I found scientific papers comparing “cold pressed” juice with centrifugal juice.
Great, I thought.
Until I looked at the equipment.
In at least one study, the “cold press” machine wasn’t a traditional two-stage hydraulic press at all. It was a vertical slow juicer.
That matters.
Because if we put auger extraction and two-stage hydraulic pressing into the same category, we’re potentially comparing very different processes under one name.
It’s a little like comparing steaming and boiling because neither involves frying.
Technically there may be something that connects them but mechanically they aren’t doing the same thing.
Perhaps instead of simply asking:
“Is this cold pressed?”
we should be asking…
“How was this juice actually extracted?”
Then there’s oxidation
Another common belief is that slower extraction automatically means less oxidation.
Again, it isn’t quite that simple.
High-speed processing can introduce heat and air, which is one reason slower extraction methods became attractive.
But grinding plant tissue also ruptures cells.
Once those cellular structures are disrupted, compounds and naturally occurring enzymes that were previously separated can encounter one another and oxygen.
So oxidation isn’t determined simply by whether a machine spins quickly or slowly.
We need to consider the whole process:
How aggressively was the produce disrupted?
How much air was incorporated?
What temperature did it reach?
How long was the pulp exposed before pressing?
How quickly was the juice bottled?
How much oxygen remained in the bottle?
How cold was it kept?
And how long did it sit before being consumed?
Suddenly the machine is only one part of the story.
Freshness may be more important than the marketing terminology
This was another part of the research I found particularly interesting.
Studies looking at juice during refrigerated storage show that bioactive compounds can change over time.
Vitamin C, phenolic compounds, carotenoids and antioxidant measurements can decline during storage, although exactly when and how quickly depends on the juice and its processing conditions.
Which raises an obvious question..
What is the point in obsessing about the extraction method while ignoring what happens to the juice afterwards?
A beautifully extracted juice that spends weeks travelling through a supply chain is a very different proposition from juice produced locally in small batches, bottled promptly, refrigerated and consumed fresh.
Perhaps the conversation needs to move beyond…
Cold pressed = good.
Towards…
What produce was used?
How was it grown?
How was it processed?
How was the plant tissue broken down?
How was the juice extracted?
How quickly was it bottled?
How has it been stored?
And how fresh is it when you drink it?
Those questions tell us far more.
What I’ve changed my mind about
I still love traditional hydraulic juice pressing.
We use a Norwalk-style two-stage process at Pressed & Blessed because I love the principle behind it: break the produce down, create the pulp and then physically press that plant material through cloth.
It’s beautifully simple.
And watching kilograms of vegetables become this intensely coloured liquid still fascinates me.
But I’m becoming much more careful about making claims such as..
“This preserves all the nutrients.”
Science doesn’t work like that.
Juicing itself changes a plant.
We remove much of its insoluble fibre. We rupture its cellular structure. We expose compounds to oxygen. We separate liquid from solids.
There are advantages and disadvantages to every processing method.
What interests me much more is understanding those differences.
And perhaps that’s the bigger lesson
Living by Design, for me, has never been about accepting something simply because it’s widely repeated.
It’s about curiosity.
Someone says something.
I think…
Is that actually true?
Then I disappear down a research rabbit hole.
😂
And this particular rabbit hole has changed the way I think about juice.
“Cold pressed” isn’t the end of the conversation.
It’s actually the beginning.
I want to know how it was pressed.
I want to understand what happened to the plant.
I want to know how efficiently different compounds were extracted.
I want to understand oxidation rather than simply fear it.
I want to understand what happens nutritionally on day one, day three, day five and day seven.
And ultimately I want that knowledge to influence how we produce our own juices.
Not because I want to claim that our method is better than everyone else’s.
But because if I’m going to put something into somebody’s body and tell them why we’ve chosen to make it that way, I want to understand the process behind it.
Not marketing.
Not wellness buzzwords.
The process.
And I’m only just getting started…
