coffee valve thinks we all know that flavor is the life of coffee,and what bring the flavor to coffee is roast.Roast,is the most important process that coffee must experience,through high temperature roast,coffee would release strong aroma,acidity,sweetness and bitterness perfectly,it becomes the wonderful taste coffee from tasteless green coffee bean.
When roasting,there would be several chemical changes,and the coffee bean would lose 15%—25% moisture.In the process of roast,the coffee bean would makes some noise like popcorn.From green coffee bean to different degree roast,the coffee bean gradually become dark and and crisp,and the aroma oil would appear on the surface.Besides,there are lots of chloric acid in the green coffee and it would be disappear when it is roasted at the same time release pleasant fruit acid such as citric acid and malic acid.If the roast is appropriate,the fruit acid would be appear perfectly,otherwise,it can’t be released or would be covered by other taste.
There have several kind of roast,you can choose different roast according to your taste.For example,American like half-city roast while British like full-city roast.
In the fifth to seventh minute,the coffee begin to release moisture,and the color become orange from light green.
When the coffee bean make the first noise and the volume expand at the same time,and the color become cinnamon,that’s the half-city roast,it also called cinnamon roast.The main taste of half-city roast coffee is acidity.In this stage,the flavor is not release well,so it is usually used in canned coffee,it can’t meet the requirement of coffee experts.
In the tenth to eleventh minute,the coffee bean become brown,that’s city roast.New York citizen like drinking city-roast coffee with some milk and sugar in the morning as breakfast,so city roast also called breakfast roast.City-roast can keep the original taste and release aroma appropriate,so many single origin coffee used this roast such as Blue mountain,Columbia,Brazil coffee and so on.
In the twelve minute to sixteenth minute,the oil start to appear,and the color is dark brown,that’s the full-city roast.Many people think in this stage,the acidity,sweetness and the bitterness in the perfectest balance point.when the color is more dark,and the oil become the caramel,it’s the full-city roast,the flavor is more mellow,is suitable to make espresso,so it also called Italian roast.
Roast give the life to coffee,that’s a difficult work.Different roast bring different taste to the coffee.If you are allergic to caffeine,you are better choose the full-city roast coffee because the caffeine would be disappear when it is roasted,so the longer the coffee roasted,the caffeine is lower.It is said that there is only a half caffeine in a cup of espresso,compare to other single original coffee.