A new study published in the journal Flavour set out to find just how much influence the tint of your coffee cup has on your perception of the flavor. Turns out, white cups significantly affect how sweet you find your morning brew. Subjects were served a latte prepared with full-cream milk and no sweeteners in three sets of mugs: blue, clear and white. Those who sipped lattes from white ceramic mugs found it markedly less sweet than those who sipped the same recipe from a blue mug or a clear mug.
The results were so significant that the researchers went back and ran another experiment to verify the results. In the first round, the white and clear mugs were different shapes. To correct for this and corroborate the heightened bitterness rating of the white mug lattes, the researchers used two sets of clear mugs to ensure shape consistency and added an opaque white sleeve to one set. Again, lattes in the clear mug earned a higher sweetness rating than the white. (Shed belly flab—rapidly—with one of the 4 Teas That Melt Fat!)
Though the researchers frame their results in terms of how companies package and serve their coffee, the findings are applicable to the home brewer, too. Looking to cut back the sugar in your morning cup of joe? Try swapping out your mug as a first step.