Not to be confused with the similar-sounding strudel (a famous Viennese pastry), streusel is a crumbly, crunchy dessert topping that's common in Central Europe.
A mixture of flour, butter and sugar—plus optional flavorings like cinnamon, vanilla extract, lemon zest or nuts—it's sprinkled atop coffee cakes, muffins, fruit-based crumbles and other sweets before baking. (The word is derived the German verb "to scatter.")
Streusel is also the name of a round Alsatian brioche covered in sweet shortcrust pastry and sometimes filled with cream.
Reference: What is a crumble? (Cookthink)
Recipe: Maple Plum Crumble (Cookthink)
Fermentation is a process where certain so-called "good" or "preferable" microbes living on the surface of plants flourish and feed on those plants, supressing the growth of "bad" bacteria. These microbes also produce substances like lactic acid and alcohol, preserving food's texture and nutrients and enhancing its taste and flavor.
Commonly fermented foods and drinks include wine and bread, where yeast is encouraged to consume sugar. To make olives, preserved lemons, sauerkraut and pickles, vegetables are submerged in brine to create the proper oxygen-free atmosphere for good bacteria to flourish, extending their shelf-life.
