I have a bachelor's degree in Oenology and Beverage Technology and I would like to apply for a master's degree in Brewing Science and Technology. However, my bachelor's ECTS in mathematics and statistics are far fewer than those required by the M.Sc. Is there a way to add more ECTS to my degree? Could I take a course to reach the minimum requirements?
Adding ECTS to your degree after you graduated is probably not possible.
However at least some European universities will let you enrol to a single course/module: you can attend one or more courses without being enrolled for a degree and earn a certificate for the ECTS you need. You are after some generic not-too-advanced Mathematics/Statistics training which you can find in many scientific (Biology?) degrees at most institutions, so it should be quite easy to find something suitable for you.
Depending on the circumstances this could be expensive, demanding and takes some time (if you really need the credits before applying you need to wait at least one semester, possibly one year), so it is probably better to contact the department offering the MSc you are interested in to try to decide whether it's worth doing.
I agree with the other answer that it most likely is not possible to add credits to your current degree.
However, sometimes pre-master courses are offered, specifically to fill any gaps between your background and the background expected for the master's program. You should check with the department/institution where you want to do the M.Sc. if they offer such an option.