I added a spoon of liquid herbal tea concentrate that I subsequently discovered was not under hashgachah to a porcelain cup of hot water shortly after boiling the latter in a microwave. The amount of concentrate added was less than 1/60 of the volume of the water in the cup, but was certainly sufficient to impart flavor to the water owing to the concentrated nature of the product. The water was no longer boiling when the concentrate was added; at least half a minute elapsed between removing the cup from the microwave and adding the concentrate. Does the cup need to be discarded under such circumstances? If a metal spoon was used to stir the hot water after adding the concentrate, does the spoon need to be kashered?
After consultation with a kashrus expert, both the cup and he spoon do not need to be kashered. The reason is because even if the was some non kosher ingredients in the tea concentrate it would be not impart enough taste to require kashering the cup or spoon. :