maybe they used this recipe .......

[rampartc]

https://passtheflamingo.com/2017/03/29/ancient-recipe-egyptian-beer-egypt-ca-5000-bce/

"Ancient Egyptian beer, called bousa, was a dietary staple. With more nutrients and less alcohol than modern beers (about 2%), it could be drank throughout the day and was actually safer to drink than water due to the lack of modern sanitation. Laborers were often paid in beer rations (the workers on the Great Pyramids at Giza received 4-5 liters a day). Beer was served at every Egyptian meal, especially among the lower classes. Multiple people often shared the same beer vessel using long reed straws, creating a visual effect similar to 1950s teenagers sharing an ice cream float (or modern college kids sharing a fishbowl of liquor and fruit juice at that one restaurant that doesn’t card). The straw was both social and practical: bousa is a lumpy semisolid rather than the liquid we might expect. The custom persists in some African cultures that make beer in a similar manner"