Which mint? The "mint" family is large. And where did the mint used come from?

Blanched? No. We call that making tea. ;)

FataMorgana

Was your mint budding to bloom or had it already bloomed? Herbs will take on a bitter taste if allowed to bloom. That is why it is recommended that you don't let them bloom till late in summer to set seed for the coming year. Another thing that could cause a bitter taste, some people water their plants with recycled water. Soaps could affect the taste too. Just a couple of thoughts that might help... gremmy