According to Briggs (Brewing: Science and Practice, p. 482), increased hydrostatic pressure slows yeast growth, thus suppressing the production of phenols and esters.
When you're asking for the difference between ethanol, esters, and phenols, what are you hoping to learn? Ethanol is your primary alcohol, and both esters and phenols are metabolic byproducts/intermediates that contribute distinct flavors to beer. Esters tend to be fruity and phenols tend to be spicy or astringent.
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