1.You are permitted to try to attract attention, but there are rules about how to do this. Do not call out, tap coins on the counter, snap your finger or wave like a drowning swimmer. Do not scowl or sigh or roll your eyes.
2.And whatever you do, do not ring the bell hanging behind the counter-this is used by the landlord to signal closing time.
3.The key thing is to catch the bar worker's eyes. You could also hold an empty glass or some money, but do not wave them about. Do adopt an expectant, hopeful, even slightly anxious facial expression.
4.If you look too contented and complacent, the bar staff may assume you are already being served.
5.Are these events connected? Looking only at individual extreme events will not reveal their cause, just like watching a few scenes from a movie does not reveal the plot. But, viewed in a broader context, and using the logic of physics, important parts of the plot can be understood.
6.For fermentation to take place you need raw material, or feedstock, as it is known in the biofuels industry. Anything will do as long as it can be broken down into sugars, with the byproduct ideally burnt to produce electricity to run the plant.