Beer with a high alcohol content is not necessarily high in residual sugars. Similarly low alcohol beers are not guaranteed to be low in residual sugar.
The alcohol by volume measure used is determined by the level of attenuation (change between start and finish gravity) during fermentation. A beer at 5% will have attenuated from the start gravity by a value of around 37; ie if the gravity at the start of fermentation was 39 and at the end of fermentation was 2 the alcohol, content would be around 5%. The residual fermentable carbohydrates (sugars)is, therefore, small. If, however, the start gravity for the brew was 50 and the finish gravity was 13 the alcohol by volume would be 5% but the residual sugars would be significantly higher (attenuation to zero would increase the alcohol by volume measure by nearly 2%).
Low alcohol beers drink 'thin' because, rather than brew from 'goods' with a high converted diastatic malt content, other, cheaper sugars derived from cane, beets etc are used to increase the gravity at the start of the fermentation. Many UK breweries (certainly all I have visited to see the process) use some added 'sugars' in the process (its cheaper!) - unlike, for example, German breweries where legislation ensures that all of the fermentable carbohydrate is derived from malts.
if you want to check your preferred brew simply purchase a hydrometer, drop it into a pint, or better still a measuring glass full of beer, and observe the gravity - the closer it is to zero the less residual sugars in the beer.
The alcohol by volume measure used is determined by the level of attenuation (change between start and finish gravity) during fermentation. A beer at 5% will have attenuated from the start gravity by a value of around 37; ie if the gravity at the start of fermentation was 39 and at the end of fermentation was 2 the alcohol, content would be around 5%. The residual fermentable carbohydrates (sugars)is, therefore, small. If, however, the start gravity for the brew was 50 and the finish gravity was 13 the alcohol by volume would be 5% but the residual sugars would be significantly higher (attenuation to zero would increase the alcohol by volume measure by nearly 2%).
Low alcohol beers drink 'thin' because, rather than brew from 'goods' with a high converted diastatic malt content, other, cheaper sugars derived from cane, beets etc are used to increase the gravity at the start of the fermentation. Many UK breweries (certainly all I have visited to see the process) use some added 'sugars' in the process (its cheaper!) - unlike, for example, German breweries where legislation ensures that all of the fermentable carbohydrate is derived from malts.
if you want to check your preferred brew simply purchase a hydrometer, drop it into a pint, or better still a measuring glass full of beer, and observe the gravity - the closer it is to zero the less residual sugars in the beer.