One way to tell if olive oil has high polyphenols is by looking for the words "high phenolic" or "polyphenol-rich" on the label. You can also look for olive oil that is labeled as "cold-pressed" or "first-pressed," as these methods of production are known to retain the highest levels of polyphenols in the oil. Another way to tell if olive oil has high polyphenols is by its color and taste. High polyphenol olive oil is typically dark green in color and has a strong, slightly bitter taste with a pepperiness detectable as an aftertaste and in the throat. This is because the polyphenols give the oil its color and contribute to its distinctive flavor and burn. In contrast, lower-quality olive oil is typically pale in color and has a milder, less complex flavor.