This suggests that sugar was introduced to Western Europe by the Crusades. So depending on the exact date, the brewers may not have had sugar alternatives to honey at all! Crazy to think that something considered such a basic ingredient in cooking may not have been available at all.
Well, where would it have grown? Sugar cane is a tropical plant. It's only modern (well, post Age of Sail) transportation logistics that makes it available to global consumers.
The method for extracting sugar from beets was discovered only in the Renaissance (most typically attributed to the French agronomist Olivier de Serres (1539-1619), so medieval people wouldn't have access to beet sugar even if they had beets.
https://makingsenseofsugar.com/all-about-sugar/history-of-su....