What are "UK Units" when it comes to beers?

A UK unit of alcohol is 10 ml by volume, or 8 g by weight, of pure alcohol. In other words, the percentage alcohol by volume (%abv) of any drink equals the number of units in one litre of that drink. So in your case 8.5% x .33L = 2.8 units or 28 ml of pure alcohol. FYI: The UK recommended top limit of alcohol consumption is 21 units of alcohol per week and no more than 4 units per day.