Supermarket sourdough has become big business and brands like Jason’s Sourdough position themselves as “clean label,” “no preservatives” and a more authentic alternative to standard factory bread. For those reducing UPFs, it has become a go-to choice (including my own personal favourite) – a convenient option for people who want something that feels closer to traditional bakery sourdough without making it at home.
However, new information suggests the picture may be more complicated — and that Jason’s could fall into the ultra processed food (UPF) category.
So is Jason’s sourdough UPF? Let’s take a look at what’s been going on.
Contents
What Jason’s Claims
Jason’s markets itself as:
- “No preservatives”
- “No additives”
- “Long fermentation”
- “Real sourdough mother culture”
- “Clean label”
Most packaging lists just:
wheat flour, water, salt, fermented wheat flour
On the surface, this looks simple. But the critical ingredient here is fermented wheat flour and what that actually means in modern industrial bread-making.
The Real Issue: What Is “Fermented Wheat Flour”?
In September 2025, the Real Bread Campaign / Sustain published a major investigation exposing the widespread use of fermented wheat flour in supermarket loaves:
🔗 https://www.sustainweb.org/news/sep25-fermented-wheat-flour-dirty-secret-behind-factory-loaf-clean-labels/
Key findings:
- many large bakeries use fermented flour treated with specific bacteria
- these bacteria produce propionic acid, which stops mould
- propionic acid functions as a preservative
- because it is produced via fermentation, it does not need to be listed as an additive or E-number
This creates a “clean label” effect — a loaf that looks simple but is still being preserved for longer shelf life.
Jason’s Private Confirmation
In private correspondence shared with Sustain on 3 November 2025, Jason’s confirmed:
“The fermented wheat flour does generate propionic acid, which has a preservative function.”
Jason’s defended its “no preservatives” claim by saying:
“It occurs naturally in the process – hence why we say no added preservatives.”
However, this is a technical loophole — the function of the ingredient is still preservation.
The Federation of Bakers Confirms It Too
On 15 October 2025, the Federation of Bakers formally stated that fermented wheat flour is used as a preservative in bread production.
That statement is published here:
🔗 https://www.sustainweb.org/news/oct25-fermented-wheat-flour-is-a-preservative-confirms-bakery-trade-body/
This means the use of fermented wheat flour as a preservative is industry-standard and no longer in dispute.
Public Messaging: Direct Questions, Indirect Answers
This is where concerns around transparency intensify.
Consumers and the Real Bread Campaign have repeatedly asked Jason’s on Instagram and other public platforms whether fermented wheat flour is being used as a preservative.
Jason’s replies publicly with statements like:
“Our mother culture is the sole leavening agent.”
“Fermented wheat flour is produced with probiotic bacteria.”
“It is not an additive and not an added E-number.”
However…these responses do not answer the specific question at all.
They emphasise “naturalness” and “probiotics,” but avoid acknowledging the preservative function that they privately confirmed to Sustain.
This mismatch between private clarity and public vagueness is what concerns so many consumers -including me. The Real Bread Campaign has also pointed out the absence of a direct answer. When I buy from a brand, I expect honesty about their ingredients, not carefully worded replies. Jason’s has built a strong following among people avoiding UPFs (myself included), which makes their reluctance to be transparent even harder to overlook.
Is Jason’s Sourdough UPF?
Based on the NOVA classification system, yes — or at the very least borderline UPF.
Here’s why:
1. A preservative is intentionally generated
Whether added directly or produced by fermentation, a preservative is still a preservative.
2. The technique is industrial
Propionic-acid-producing fermentation is not a traditional sourdough practice.
3. Ultra-processing is about function, not labels
Even if it avoids E-numbers, if it behaves like a preservative, it counts.
4. Clean-label loopholes are a UPF hallmark
Hiding industrial functions behind “natural fermentation” fits the definition of clean-label ultra-processing.
Therefore:
Jason’s cannot be considered non-UPF bread.
Why This Matters
Many shoppers choose Jason’s instead of industrial bread specifically to avoid UPFs. However, if a product uses a preservative (even one generated through fermentation) and markets itself as “no preservatives,” that is misleading by omission.
Consumers who want transparency deserve clear answers – not technical wording that obscures the truth.
Better Non-UPF Bread Alternatives
If you want genuinely non-UPF bread, look for:
- flour, water, salt only
- loaves with short shelf lives
- no “fermented wheat flour” listed
- no preservation claims
Real sourdough doesn’t require industrial preservation techniques.
Final Verdict
Jason’s Sourdough is marketed as simple, honest, and artisan-like. However, the confirmed use of fermented wheat flour as a preservative-producing ingredient places it firmly in the UPF or borderline-UPF category.
It isn’t the worst supermarket bread — but it’s not what many consumers think they’re buying. It certainly wasn’t what I thought I was buying.
For those avoiding UPFs, Jason’s is not a true non UPF option.
This article is based on publicly available information from Sustain, the Real Bread Campaign and Jason’s Sourdough. It reflects my personal interpretation of those findings and is not intended to make any legal, medical or professional claims. Readers should consult official sources or product labels for the latest information.