One thing to show them is that useful fermentation occurs almost everywhere. Beer is the obvious example but bread, yogurt and sauerkraut (or kimchi) and "real ginger beer" are just as useful and widespread. Even tobacco is (dry) "fermented" over a year to give a more refined flavour and aroma.

I would try making real ginger beer using the ginger beer SCOOBY because it is mostly the same process as fermenting beer, produces a non (or weakly) alcoholic drink, is a good pro-biotic and can be on "free issue" to the children for drinking. It is also tasty and very easy to keep and store and rarely if ever gets infected. The other easy fermented thing to make is sauerkraut which is also a good pro-biotic and digestive aid. The trick is to use fresh cabbages cut fresh from the garden as they contain maximum sugars to be fermented.

One neat trick I have seen for kids to demonstrate fermentation and CO2 gas production is to put a yeast and sugar solution in a balloon and tie it up. The fermentation inflates the balloon to varying degrees. Now alter the yeast, water and sugar amounts. Alter the temperature. How do the balloons behave? What temperature does fermentation stop (both high and low)? A whole host of interesting experiments!

And if the kids want to drink "small beer" then yeast can be used to make fast fermenting fruit flavoured drinks with minimal alcohol from flavoured sugar water. I recommend using plastic PET fizzy drinks bottles for containing any such drinks. Any mistake will not result in such a dangerous bottle fracture.

One thing to show them is that useful fermentation occurs almost everywhere. Beer is the obvious example but bread, yogurt and sauerkraut (or kimchi) and "real ginger beer" are just as useful and widespread. Even tobacco is (dry) "fermented" over a year to give a more refined flavour and aroma.

I would try making real ginger beer using the ginger beer SCOBY because it is mostly the same process as fermenting beer, produces a non (or weakly) alcoholic drink, is a good pro-biotic and can be on "free issue" to the children for drinking. It is also tasty and very easy to keep and store and rarely if ever gets infected. The other easy fermented thing to make is sauerkraut which is also a good pro-biotic and digestive aid. The trick is to use fresh cabbages cut fresh from the garden as they contain maximum sugars to be fermented.

One neat trick I have seen for kids to demonstrate fermentation and CO2 gas production is to put a yeast and sugar solution in a balloon and tie it up. The fermentation inflates the balloon to varying degrees. Now alter the yeast, water and sugar amounts. Alter the temperature. How do the balloons behave? What temperature does fermentation stop (both high and low)? A whole host of interesting experiments!EDIT: One can also use "snaplock" type plastic storage bags instead of balloons

And if the kids want to drink "small beer" then yeast can be used to make fast fermenting fruit flavoured drinks with minimal alcohol from flavoured sugar water. I recommend using plastic PET fizzy drinks bottles for containing any such drinks. Any mistake will not result in such a dangerous bottle fracture.