酯

Left 酉 is the wine-jug radical, originally a side-view drawing of a fermentation vessel. Indexing radical, anchoring 酯 in the alcohol / fermentation family (酒 wine, 醋 vinegar, 醉 drunk, 酸 acid). 酯 is the modern chemical term for ester - a class of compounds formed from acid + alcohol, so the radical is semantically apt.

Right 旨 supplies the sound - zhǐ straight through, no drift. The 'purpose / tasty' meaning doesn't enter; 旨 is a pure sound-tag. The character was coined for organic chemistry in the late 19th century, picking 酉 wine + 旨 sound as a Sinified term for what English calls 'ester,' itself derived from German Essig 'vinegar.'