Rebecca Andersson / Tasting Table
Olive oil, an ancient Mediterranean food staple long used to enhance the pleasures of food, is far from a one-note ingredient. Depending on various factors, like the olive variety, growing region, method of extraction, and any further refinement or blending, it can range from delicate and floral to bold and peppery. A good olive oil can transform food — not just as a cooking medium, but as a finishing touch that brings brightness, depth, and complexity to the dish. This is why Martha Stewart advises you always have at least two different olive oils on hand — one for everyday cooking, and another for drizzling or dipping.
For this ranked roundup, I sampled all five Kirkland Signature olive oils available at my local Costco warehouse. Tasting them on their own (as well as with a piece of bread), and ranking each olive oil as a stand alone ingredient revealed nuances that often get lost in daily use — from color that hints at ripeness, to aroma that fills the glass, to viscosity or mouthfeel, and finally, to the intricate balance of flavors — grass, fruit, bitterness, nuttiness, and peppery spice — that lingers on the palate.
One clear star emerged from the lineup — but each olive oil brought something different to the table, so let’s take a closer look at the differences and highlights of each one below.
5. Kirkland Signature 100% Italian extra virgin olive oil
Rebecca Andersson / Tasting Table
Italy’s olive oils have a reputation for being distinct from Spanish ones, so I was curious to try the Kirkland Signature 100% Italian extra virgin olive oil. Aromatically, it instantly leaned sharply green, promising boldness before the sip. At first taste, the flavor was indeed grassy, herbaceous, and fresh, but it very quickly turned assertive with a strong bitterness. The bitter flavors kept building into rather peppery, spicy notes that lingered at the back of the throat. Wowza! The aftertaste was sharp and harsh. As for the mouthfeel, it was medium-bodied, yet gripping on the tongue in a way that amplified the oil’s bold intensity.
At $27.99 for a 2-liter bottle ($14 per liter), this olive oil is also one of the most expensive Kirkland options. Although the label claims that this oil is excellent for both cooking and finishing fresh food, it seemed more like a specialty choice for those who explicitly enjoy bitterness and spice, rather than an everyday oil. While this Italian olive oil might not be for everyone, its boldness could shine drizzled over hearty dishes, like hearty stews and grilled meats, roasted root vegetables, or bean soups, where strength and bitterness may be desired. More delicate dishes or baked goods would be overwhelmed by the intensity of this oil. For these reasons, I found this oil to be less versatile, which is also why I ranked it the lowest.
4. Kirkland Signature olive oil
Rebecca Andersson / Tasting Table
My second-to-least favorite oil, the Kirkland Signature olive oil, was diametrically opposed to the Kirkland Signature 100% Italian extra virgin olive oil. The refined olive oil comes from up to 11 different countries of origin, and is blended with 15% extra virgin olive oil. Pouring the oil onto a plate, I could immediately see that it was much thinner and less viscous than the other oils. It was also surprisingly pale in color and nearly odorless, though it did have some grassy notes. On the palate, it had a runnier mouthfeel with a mild and neutral taste, offering very little distinct olive oil flavor, and next to no aftertaste.
While this olive oil lacks personality, its neutrality makes it useful as a cooking oil where you want the flavors of the cooked ingredients to dominate the dish. I also think it would work perfectly as an olive oil for marinades. In my taste test, though, it simply felt flat and uninteresting.
At $19.99 for 3 liters ($6.66 per liter), it is the cheapest of all the Kirkland Signature olive oils per liter. That makes it a budget-friendly utilitarian oil for high-heat cooking, baking, and even salad dressings where other flavors shine, but not very exciting for dipping or finishing off dishes with a drizzle. I’d recommend the Kirkland Signature olive oil for all your everyday frying and stir-fry needs, baking polenta cake, or as a neutral salad dressing or marinade base oil when robust flavor from the olive oil itself isn’t a priority.
3. Kirkland Signature organic extra virgin olive oil
Rebecca Andersson / Tasting Table
The only certified organic option in the bunch, the Kirkland Signature extra virgin olive oil, struck me as a solid middle-ground olive oil, which is why I rated it right in the middle of the five. Like the refined olive oil above, it also comes from up to 11 different countries of origin. It had a mild, yet complex aroma, with earthy undertones and a touch of fruit that hinted at depth of flavor. Upon tasting it, I found the mouthfeel to be smooth and medium-bodied, pleasantly coating the palate.
The flavor was complex, yet gentle, offering mild fruitiness and hints of grass. A touch of bitterness added structure, but without the spiciness found in the Italian olive oil. It felt balanced and layered, making it well-suited for simple applications where subtlety matters, like dressing fresh greens or finishing roasted vegetables. Full yet approachable, I thought the organic Kirkland Signature extra virgin olive oil was a well-rounded oil that could work for nearly any use, from cooking to dressing up salads to finishing drizzles on hummus, meat, and veggie dishes alike.
At $18.99 for 2 liters ($9.50 per liter), it is an affordable and reliable oil that’s interesting and complex enough for bread-dipping, but also mild enough that it is adaptable for cooking. This makes it the best all-around choice for flavor, value, and everyday cooking. Use the Kirkland Signature organic extra virgin olive oil to dress your everyday salads, sauteed greens, roasted vegetables, or to finish fish.
2. Kirkland Signature Siurana extra virgin olive oil
Rebecca Andersson / Tasting Table
The only single-origin olive oil sold in glass, the Kirkland Signature extra virgin olive oil from Siurana, a protected designation of origin in Spain, opened with an uplifting, fresh, grassy aroma. Pouring it, I noted its rich, golden, luminous color and rather viscous consistency. Crafted predominantly from Arbequina olives, its flavor was light and silky, evoking notes of spring herbs, fruit, and freshly cut grass. The balance of flavor was impressive — neither bitter nor spicy, just fresh, clean, and absolutely delicious. Its smooth, clean finish made it easy to enjoy on its own as well as with some rustic sourdough bread.
While I found the Kirkland Signature extra virgin olive oil from Siurana to be quite elegant and the best tasting olive oil of the lot, it is also the most expensive at $14.99 per liter. Though I think it would perform excellently as a cooking oil, the steeper price tag makes this oil less of an everyday workhorse and more of a specialty oil for dipping or drizzling as a finishing oil over vegetables and fish, or whenever you want to add some finesse at the table. I recommend this delicious Kirkland Signature Siurana extra virgin olive oil as a drizzle over fresh salads, tomatoes, burrata, grilled vegetables and fish dishes, ice cream, in coffee, or simply enjoy with bread.
1. Kirkland Signature 100% Spanish extra virgin olive oil
Rebecca Andersson / Tasting Table
Coming in as my No. 1 choice, this Kirkland Signature 100% Spanish extra virgin olive oil immediately impressed with a delightfully sweet, grassy aroma that promised freshness and flavor. It poured a slightly darker golden hue with more viscosity than the other olive oils in the lineup, signaling richness and body. The mouthfeel was medium to heavy, leaving a lingering impression and satisfying weight on the palate. It had a rustic character, making it seem well-suited for both cooking and dipping bread, as well as a delicious finishing drizzle. Flavor-wise, it combined the freshness of grass and fruit with a hint of bitterness, though no spiciness developed, making it a solid, workhorse oil for everyday use.
Sold for $24.99 in a 3-liter jug ($8.33 per liter), it is a value pick for an oil that is flavorful enough for bread and salad, yet affordable enough for everyday cooking. This Kirkland Signature 100% Spanish extra virgin olive oil is versatile as both an everyday cooking and finishing oil, as well as for bread dipping, salad dressings, drizzling over pasta, and grilled vegetable and meat dishes.
Methodology
Rebecca Andersson / Tasting Table
To ensure a fair and consistent tasting, I sampled all five Kirkland Signature olive oils available at my local Costco, evaluating them at room temperature, using the same fresh sourdough loaf as a tasting medium. This allowed me to experience both the flavor and mouth-coating quality in a practical, everyday context.
During the tasting, I first opened the bottle and assessed the aroma, noting fresh, grassy, herby, fruity, or earthy qualities, as well as oils that were neutral or bland. Next, I poured a small amount of oil onto a white plate, observing the color and viscosity of each oil, ranging from pale to deep golden, as an indicator of ripeness and body. When tasting the oil, I first tried each oil alone, paying attention to mouthfeel, and evaluating whether the oils were light, medium, or heavy, and how they coated the palate. Next, I dipped pieces of sourdough bread into the oil and ate several pieces in a row. Flavor progression was most important, from the initial taste impression to any developing bitterness or spiciness, to any lingering aftertaste. Finally, I considered the utility of each oil, comparing the price per liter to its versatility based on the above-mentioned sensory qualities.
Tasting oils side by side in a single session made subtle contrasts immediately apparent, highlighting nuances that are often lost when oils are incorporated into cooked dishes. Though I am not an olive oil sommelier, my approach mirrored professional tasting techniques while remaining practical for home cooks who want to evaluate their options.
Dining and Cooking