Use Brut or Extra Brut Champagne. Sparkling wine terminology can be a bit confusing with respect to the rest of the wine world. Sec Champagnes, also noted as Dry, are on the sweeter side. Typically a dry wine means it is not sweet but not in this case. Brut, Extra Brut, and Brut Nature wines all have less sugar.
Of course, if you like a sweeter mimosa, then Extra Sec, Sec, and Demi Sec Champagnes might be better for you. Doux Champagne for a mimosa is basically a soda pop.
Prosecco is a great low-cost alternative to Champagne for mimosas, but it doesn’t quite bubble the same. That said, it is much easier on the wallet.
Both the sparkling wine and the orange juice should be very cold.
Add the bubbly to the glasses first. This allows the Champagne to bubble up but not cause a mess. If there was OJ in the glass, the bubbles could cause it to spill over.
Never stir your mimosa. The addition of the orange juice to the bubbly is more than enough to mix the ingredients. Stirring will only flatten the cocktail.
Ix-nay on the itcher-pay too. That is, never make a pitcher of mimosas ahead of time. It’s just another way you will lose those precious bubbles.