The key to this sentence is the description of the wine aficionado (or expert) as a "purist," or someone who insists on the purity of things. Since he rejects the first blank, you can assume it will be an antonym of pure. You can predict mixture, which fits in the context. However, he prefers the second blank, so this should be a synonym of pure and the contextual word "simple."
For the first blank, the best match for your prediction is choice (A) amalgamation. This is an exact synonym of your prediction, mixture. Choice (B) dissonance, which means "a disagreeable combination," seems plausible. A purist would definitely find a mixture of two wines to be dissonant. However, we need a word that states this mixture has occurred for the sentence to make sense. Similarly, choice (C) enigma means "puzzle," which may also be applicable to such a mixture but, again, lacks the necessary meaning of "mixture." For the second blank, choice (E) unadulterated matches your prediction best. Choice (D) pragmatic means "practical" and does not fit as well as unadulterated in context. The wine aficionado does not prefer something for its practicality but for the taste; therefore, this choice would be misleading in the sentence. Choice (F) opaque, which means "impossible to see through," may similarly be applicable to the wine; however, nowhere in the sentence is the color implied or relevant.