Kosterina Olive Oil: An Honest Review and How It Compares
Kosterina olive oil is a Greek extra virgin olive oil brand founded in 2016 by Katerina Mountanos, made from early-harvest Koroneiki olives grown in southern Greece. When we checked, its Original EVOO listed 578 mg/kg polyphenols (November 2025 harvest) and its certified-organic Everyday EVOO 453 mg/kg (December 2025 harvest), each with a linked chemical analysis. A 500ml Original bottle was $32. The brand also sells flavoured oils, olives and olive-oil skincare. Checked 20 October 2026.
This review reads the brand's own shop pages; we have not tasted a current bottle.
The Short Answer
- Kosterina is a Greek extra virgin olive oil brand, founded in 2016, built around early-harvest Koroneiki olives from southern Greece.
- Its headline strength is a published polyphenol figure: 578 mg/kg for the Original EVOO's November 2025 harvest, with the latest chemical analysis linked from the product page.
- The Organic Everyday EVOO is made from certified organic Koroneiki olives and listed at 453 mg/kg; the Original is not sold as certified organic.
- The brand states its olives are cold-pressed soon after an early harvest, which is what you want for flavour and polyphenol retention.
- Product pages print the harvest month, which many brands do not.
Who Kosterina Is, and What They Actually Sell
Kosterina was founded in 2016 by Katerina Mountanos, whose family comes from Koroni — a fishing village in the south of Greece that happens to sit in the heart of Koroneiki olive country. The brand name is a blend of her name and her husband Kostas's. The founding story is a common and honest one: she found that the "Greek extra virgin" oil on American shelves tasted nothing like the oil her family pressed back home, and set out to import the real thing.
That origin matters, because it shapes what Kosterina is good at. The company started with one product — a single-origin, early-harvest extra virgin olive oil — and has since grown into a broader Mediterranean range: a USDA-certified organic "Everyday" oil for cooking, flavoured oils, vinegars, olives, and even olive-oil skincare. For our purposes, the part that matters is the extra virgin olive oil, and on that the brand has a clear, defensible position.
The Kosterina Range and Prices
Prices below are from Kosterina's US online shop, checked on 20 October 2026; multi-bottle packs and subscriptions are priced separately.
| Product | What the shop states | Price (20 Oct 2026) |
|---|---|---|
| Original Extra Virgin Olive Oil, 500ml | 100% Koroneiki, early harvest, cold pressed; 578 mg/kg polyphenols; harvested November 2025 | $32 |
| Original Extra Virgin Olive Oil, 375ml | As above, smaller bottle | $25 |
| Original Extra Virgin Olive Oil, 3L tin | Larger format of the Original | $125 |
| Organic Everyday Extra Virgin Olive Oil | Certified organic Koroneiki; milder, for cooking; 453 mg/kg; harvested December 2025 | $26 (single bottle) |
| Organic Everyday EVOO tin, 500ml | Wide-opening tin for cooking | $22 |
The shop also lists flavoured olive oils, single-serve EVOO shots, vinegars, olives and skincare such as an Extra Virgin Oil Balm, which is why some searches ask whether Kosterina is a beauty brand: it is primarily an olive oil company with a wider range.
Polyphenols: Kosterina's Real Strength
Polyphenols are the antioxidant compounds in olive oil that the research community has spent the most time on — oleocanthal, oleuropein, hydroxytyrosol, and tyrosol among them. The EU has a registered health claim (Regulation 432/2012) for olive oil polyphenols protecting blood lipids from oxidative stress, set at 5 mg of hydroxytyrosol and its derivatives per 20 g of oil. Higher-polyphenol oils tend to taste more peppery and bitter, and they hold up better to time and heat. This is genuinely the most evidence-grounded thing you can say about why a fresh, well-made olive oil is worth choosing.
When we checked on 20 October 2026, Kosterina's Original EVOO page listed a polyphenol count of 578 mg/kg for the November 2025 harvest, and the Organic Everyday page listed 453 mg/kg for the December 2025 harvest, each with a link to the latest chemical analysis. That is a specific, checkable disclosure, and a brand that publishes a number with the analysis behind it is doing the right thing by its customers.
One fair, category-wide point worth knowing: polyphenol figures depend on the testing method used. Different laboratory methods can return different numbers for the same oil, so the most useful comparison is always like-for-like — the same method across the oils you are weighing up. This is not a criticism of Kosterina, which tests independently; it is simply how to read any polyphenol claim sensibly, theirs or anyone else's.
Early Harvest and Same-Day Pressing: What Kosterina Gets Right
Two things drive polyphenol content and flavour more than almost anything else: when the olives are picked, and how quickly they are pressed. Kosterina picks early, while the olives are still unripe, which yields a smaller amount of more concentrated, more bitter, more antioxidant-rich juice. It then presses the same day the fruit is picked, which limits the oxidation that begins as soon as an olive leaves the tree.
Cold extraction, generally understood as mechanical extraction at no more than 27°C, protects heat-sensitive compounds that refining removes, and speed from grove to press protects them further. Kosterina's published process follows that logic closely.
How to Judge Any Olive Oil You're Considering
If you are comparing Kosterina with anything else, the same handful of questions cuts through most marketing. Is it genuinely extra virgin, cold-pressed, and unrefined? Is the origin specific and traceable, or vague? Is it early-harvest? Is it sold in dark glass or tin that protects it from light? And is there a polyphenol figure — ideally tested independently — rather than a bare adjective like "premium"?
Kosterina answers most of these well: specific origin, early harvest, dark bottle, a tested polyphenol number. Those are the markers of a serious oil. For a fuller walkthrough of how to read a label and what each term actually means, see our guide to choosing a quality olive oil. The point here is simply that the questions are the same whichever bottle you are holding — and that a good brand will have plain answers to all of them.
Is Kosterina a Good Olive Oil Brand?
On the evidence it publishes, yes. Kosterina names its cultivar and region, prints the harvest month, and links a chemical analysis behind a specific polyphenol figure for both of its plain extra virgins, with a certified organic option for everyday cooking. Its oils are priced above supermarket extra virgin, and the stated figures describe a particular harvest, so check the harvest month on the bottle you buy.
How It Compares with a Single-Estate Oil
Kosterina publishes a polyphenol figure for each current harvest; where our oil differs is the source itself: one estate we farm ourselves near Marrakech, rain-fed, cold-pressed, unfiltered and with every batch independently tested.
| Kosterina Original EVOO | Sidr & Stone Marrakech (500ml) | |
|---|---|---|
| Source | Koroneiki olives grown in southern Greece; grove not named | One estate near Marrakech, Morocco, which we farm ourselves |
| Organic status | Original not sold as certified organic; Everyday line certified organic | Organically grown; certification in progress |
| Pressing | Cold pressed after an early harvest | Cold-pressed |
| Filtering | Not stated | Unfiltered |
| Testing | Polyphenol figure and chemical analysis published per harvest | Every batch independently tested |
If a published polyphenol figure for a Greek Koroneiki oil comes first for you, Kosterina covers it. If you would rather trace your oil to one farm and one batch, our Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml) is made for that.
Why Sidr & Stone
Sidr & Stone makes one olive oil, from one farm we work ourselves, in small batches you can trace.
- Sidr & Stone's olive oil is single-estate: our own family-owned farm near Marrakech, Morocco, with every step controlled from tree to bottle and no blending across origins.
- Sidr & Stone's trees are rain-fed, with no irrigation.
- Sidr & Stone's olives are organically grown, without synthetic fertilisers, pesticides or herbicides.
- Sidr & Stone has every batch independently tested.
- Sidr & Stone sells a limited single-harvest batch, picked when the fruit is ready.
- Sidr & Stone's oil is cold-pressed.
- Sidr & Stone's oil is unfiltered extra virgin and may show natural sediment.
- Sidr & Stone's oil is 100% natural: one ingredient, no additives.
- Sidr & Stone uses dark glass with a gold label to protect the oil from light.
- Sidr & Stone gives 10% of profits to charity.
- Sidr & Stone has fulfilment in the UK, EU, and US.
Frequently Asked Questions
What is Kosterina olive oil?
Kosterina is a Greek extra virgin olive oil brand, founded in 2016 by Katerina Mountanos, built around early-harvest Koroneiki olives grown in southern Greece. Its two plain extra virgins are the Original, a robust, peppery oil, and the milder Organic Everyday for cooking. The wider range includes flavoured oils, vinegars, olives and skincare.
Is Kosterina olive oil good?
On published evidence, yes: it names its cultivar and region, prints a harvest month, and links a chemical analysis behind its polyphenol figures. We have not tasted a current bottle, so this is a reading of the brand's disclosures rather than a sensory review. The Original suits finishing and raw use; the Everyday is milder for cooking.
What is Kosterina's polyphenol content?
When checked on 20 October 2026, the Original EVOO page listed 578 mg/kg for the November 2025 harvest and the Organic Everyday page 453 mg/kg for the December 2025 harvest, each linking the latest chemical analysis. Polyphenols fall as oil ages and differ by testing method, so treat each figure as a snapshot of that harvest.
Is Kosterina olive oil legit?
Yes. It is an established brand selling Greek extra virgin olive oil with a stated cultivar, region, harvest month and published polyphenol analysis, which is more disclosure than most supermarket brands offer. As with any brand, check that the harvest month on the bottle is recent and buy from the brand or an authorised retailer.
Is Kosterina olive oil organic?
The Organic Everyday EVOO is made from certified organic Koroneiki olives. The Original EVOO is not sold as certified organic, so check the specific bottle if certification matters to you. Both are listed as 100% Koroneiki early-harvest oils from southern Greece.
Is Kosterina a beauty brand?
Not primarily. Kosterina is an olive oil company whose range has grown to include olive-oil skincare, such as an Extra Virgin Oil Balm, alongside its extra virgin olive oils, flavoured oils, vinegars and olives. Its cooking oils are the core of the business and the subject of this review.
Where is Kosterina olive oil from?
From southern Greece, using Koroneiki olives; the founder's family comes from Koroni in the Peloponnese, at the heart of Koroneiki country. The brand describes an early harvest and cold pressing, and prints the harvest month on each product page, so you can see how recent the oil in a given bottle is.
How does Kosterina compare with Sidr & Stone?
Kosterina offers Greek Koroneiki oils with published per-harvest polyphenol figures and a certified organic everyday option. Sidr & Stone offers one single-estate Moroccan extra virgin from a rain-fed farm we work ourselves: organically grown with certification in progress, unfiltered, cold-pressed and with every batch independently tested.
Final Thoughts
Kosterina has earned its reputation by publishing what most brands leave out: a cultivar, a region, a harvest month and a polyphenol figure with the analysis behind it. If you are choosing between a supermarket extra virgin and a bottle like this, the published evidence is on Kosterina's side.
If you would rather trace your oil to a single estate, our Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml) is available to pre-order now, with fulfilment in the UK, EU, and US.
Our extra virgin olive oil is grown organically on our own single-estate farm on the plains outside Marrakech: we control every step from tree to bottle, and no synthetic pesticides, herbicides or fertilisers are used. It is not yet certified organic — certification is in progress, and we will publish it as soon as it comes through.
Disclaimer: This article describes Kosterina's published product information as checked on 20 October 2026; specifications, certifications, and brand practices may change, and readers should check current sources. Comparisons are made in good faith and in fair terms. Sidr & Stone is not affiliated with or endorsed by Kosterina. Olive oil is a food, not a medicine, and is not a substitute for medical treatment of any condition. For any health concern, consult a qualified medical professional.