Making coffee. #Sequence 

Making coffee. #Sequence 
 
I know that they are not strictly speaking algorithms, but recipes are a great source of inspiration when it comes to teaching algorithms. My favourite cookbook (Good Housekeeping New Basic Cookery; bought for me when I was a kid and is so good that I have re-bought it for when the time comes that it fully falls apart.) has a recipe for instant coffee! In a few easy steps, you have the instructions to make your favourite hot beverage. The more expert coffee drinkers may not appreciate the finer nuances of Nescafé, Kenco or Maxwell House but they will have to appreciate how difficult it is to mess up making the drink. These large manufacturers have their methods (we’ll call them algorithms) to make sure that the drink is the same from batch to batch and year to year; and this makes our life easier. 
 
If we want to make our perfect coffee, we need to be able to control all the variables that make it taste the way we want. Bean type, roasting time, roasting temperature, storage, coarseness of the grind, storage, water temperature, brewing time, serving method, milk and sugar? And then the most important factor, which order (sequence) the events happen in. Is it possible to mess up the process by getting things in the wrong order? Absolutely! Grinding before roasting? Brewing before roasting? You get the picture. When it comes to algorithms there is a right way and a wrong way and the results are plain to see, or taste. I’m very glad that there are people who care deeply about this kind of algorithm and want perfect results every time they (or I) brew my coffee.