Bottle Green's cordial is one of the more familiar names in the supermarket cordial aisle. The elderflower comes through cleanly - floral and lightly sweet without the cloying quality that cheaper versions tend to have. There's a faint citrus edge that keeps it from being one-dimensional. Cold-filtration is what they hang their hat on. The claim is that it preserves more of the floral character than heat-based methods would. Whether you notice the difference depends on what you're comparing it to. Mixed with water it's a pleasant, unfussy drink. Works well with sparkling water if you want something less sweet.