When do I know the beer has an herbal, spicy influence? When I notice a bit of shampoo aftertaste. And why is that? Because I have a hate relationship with coriander. I always find dishes with coriander quite difficult to enjoy, to put it in a nice way.
A few years ago, I found out that I was not unique. It looks like coriander is one of those herbs that has as many fans as detractors. You either hate it, or you love it. And I am obviously from that first group.
To me, coriander has a chemical taste, like shampoo or soap. It is quite present and intense. You could compare it to ginger qua intensity. As soon as I have a bit of it, all the other flavors fade away. It looks like the group of people who does not like coriander, all share one common thing. We have a variation of our olfactory-receptor genes. It is a genetic quirk and somehow it also has a geographic influence. In India and Central America, where coriander is very popular, there are less people with this genetic variation.
Anyways, my sensitivity to coriander helps me to fine-tune with beer tasting, as coriander is quite often used in Belgian ales, especially white beers (Witbiers). This herb adds aroma, as well as a refreshing (like citric) and spicy flavor to beer, which makes it quite a great ingredient for the types of beers mentioned. But for me, as soon as I try a beer that gives me this soap after-taste, I know it has coriander.
What is used in beer is the dried seeds and not the herb, which makes it less strong. Mainly two types of seeds are used: Indian and European. This ingredient combines very good with other spices like, the aforementioned ginger, cloves, cinnamon, cardamom, nutmeg, as well as with citric essences. Playing with these ingredients also gives us many different flavors in beer, which might be the only positive thing I can get from coriander.
Indian coriander seeds: slighly bigger, more yellow and oval.
European coriander seeds: smaller, more brown and round.
It appears to be the coriander seeds that are used in brewing, as opposed to the coriander leafs that are primarily used in food preparation.