+1.
I also think the question should be "why don't I taste (what I perceive as) alcohol". No alcohol may be one of many reasons, but I suspect there's alcohol in there.
I work professionally in wine, and an 'alcohol' taste often isn't apparent unless the wine is very 'hot' (say, 14.5% in a Cabernet). It may be you're associating acidity or tannic qualities with alcohol, and perhaps one of THOSE is missing in your latest batch. For instance, a medium-alcohol wine grown from hot-climate grapes with low acidity will have plenty of alcohol, but lacking acidity, might have no bite and taste flabby.