Let's start with the difference between a regular wine tasting and a wine glass tasting:
Wine tastings: At a traditional wine tasting, you usually taste a selection of wines from a single glass, focusing on the qualities of the wine itself. You pour the wines into the same glass, swirl it around, smell it, take a sip and taste the wines to learn more about their backgrounds and characteristics.
Wine glass tastings: In a wine glass tasting, multiple wine glasses are used, and the focus shifts to how the size and shape of the glass affect the characteristics of the wine. You take the same wine and taste it from different glasses, noticing how each glass changes the expression of the wine.