I stopped drinking but I have a lot of stale beer. Is it ok I pour out all this beer for raised beds? It seems as it is mostly water and yeast. Has anyone have any anecdotal experience with this?
I wouldn't recommend it, not least because it will stink... plus every slug and snail for miles around will be heading for your garden, they love beer - it is often used to create slug traps. The yeast content is not particularly helpful either - see here https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/using-beer-on-plants.htm#:~:text=Two%20ingredients%20in%20beer%2C%20yeast,seem%20like%20a%20good%20idea.
If we compare with for example the use of other complex liquids as irrigation candidates such as human/animal urine, dilution seems to be an approach that works. For urine the recommendation is dilution 10 times by volume. Soil type and the specific crop that the diluted product will be used on are also important. For example potatatoes, corn and squash can use diluted urine once they are established as crops. Beer might be easier to handle than urine since the alcohol is only about 3%, and once diluted that would make it 0.3%. Maybe set up a few pots of target plants and try out a test solution to observe the effect on growth, with test and control samples so that you can tip the plants out of the pots to examine the condition of the roots.
Update: There is an article in ASHS "Root-zone Alcohol Is an Effective Growth Retardant for Paperwhite Narcissus" which discusses some experiments done with non-diluted alcohol products of various kinds, including beer, on plants. There is some speculation about why beer in undiluted form would be unsuitable for watering based on sugars present in the beer which would encourage the wrong sort of bacteria for growth, but this avenue was not researched specifically. The whole point of fermenting beer is to convert sugars to alcohol. However not all sugars are susceptible to fermentation - dextrose, maltose and sucrose yes, but lactose not. I guess someone will have to pursue this a bit further to discover how much sugar remains in beer once fermentation is complete. From my own brewing it is clear that once fermentation is complete the gravity is less than 1 indicating very low sugar, but clearly you can still taste the sugar when drinking.