When you concentrate out of alcohol, you are not attaching alcohol that time. The distance between you and alcohol will increase. This can be meditation, if your concentration concentrating samādhi object or vipassanā object continuously and improvely. But, if not, it is just a sīla, precept, if you just deny to drink an alcohol, because alcohol denying is just a precept in 5 precepts, so it is just meditation base, but it still not meditation.
Sīla-training stop whole physical attachment, not just alcohol. Sīla is base of meditation, but it is not meditation because mental attachment still able to arise. When any unwholesome mind, such as attaching mind arising, that time is not meditation, because the meditation is training continuously and improvely.
Samādhi-continuous-training stop whole present mental attachment.
Vipassanā-continuous-training extirpate whole future attachment.