Lately I have been asked a lot about blonding in espresso. How do I feel about it?
Well, I don’t feel much about it anymore other than that it’s a poor indicator of a shot’s quality. A shot may taste good when it is cut off as the streams of espresso start to blond, but that is not why it is good. It just so happens that the brew recipe that suits that coffee coincides with the visual appearance of blonding.
When brewing espresso the first drops of liquid that pass through the bed of coffee and out of the portafilter are the darkest, a rich caramelised reddish brown (this does depend on coffee). Water will extract different compounds in different orders, and as the water continues to extract the colour of these streams of liquid change indicating different types of extraction. This gives a very rough idea of what is going into the cup. The traditional idea states that when the stream blonds (lightens in colour) all the tasty flavours have gone and negative flavours are then entering the cup.
A very useful book called the coffee cuppers handbook by Ted Lingle states that water will extract flavour in order - fruit acids first, then mailards, then caramels and finally burnt distillates (darker flavours). Although in essence true, don’t be led to the assumption that you can pick and choose your flavours with extraction times and lengths. You can only control flavour within the realms of what the coffee will allow. The complex play of flavours in the cup also makes brewing much more multifaceted, with other variables to be considered such as water temperature etc.
I can see why “blonding” has become an indicator of when a shot is ready. The rule stands more firmly with traditional blended coffees which contain flavour components leaning towards roasty and chocolaty.
These kinds of coffees actually extract much more easily and have less to give so “over extract” quickly, therefore a shot that blonds rarely tastes good. With such a massive change in the raw ingredient in recent times, the developing approach to roasting and so on means that “rules” need to be reconsidered.
Really it’s about understanding how to extract and brew rather than having default rules for what brews good espresso. Coffees are complex and can vary hugely from one another in flavour, this also applies to the way we approach brewing them. There does seem to be a rough guide for where most coffees brew recipes will lie, especially with a specific set up of machine, grinder and certain roasters. For us doses range from sixteen to twenty grams. Brew ratios range between fifty and seventy per cent. That’s quite a big window and there is a lot of wiggle room. The recipes for coffees we have on can sit far apart with in this window.
With what we now understand we can brew espresso, taste our coffee and then change one variable at a time noting how this affects flavour. It is important to rely on these tangible variables and taste alone. Visually I am looking for nothing more than the water to be passing through the bed of coffee evenly. That’s it.
The real concern is dose weight, shot weight, volume, time and temperature. Sometimes a brew recipe that tastes amazing will not be the prettiest to watch (on that note the crema may not showcase the “ideal” colours and texture either).
Much of what we do when brewing coffee is theorizing, attempting to understand what affects the way a coffee tastes. I can see where many of the old school rules have come from and blonding is one of them.
When I first got in to coffee I was earnestly given advice on how to brew great coffees, with indicators such as “good shots will almost hang off of the spouts at the beginning of the pour just before the drop” and so forth. I can thank a training course with the Australian barista champion at that time David Makin for dispelling the myths and setting me on my current path. I had been on several courses in Melbourne that repeated the rules, 25 ml in 25 seconds, blonding etc. I was frustrated as I felt I still didn’t understand espresso. What I had learnt didn’t relate directly to how espresso shots tasted.
The course with David opened my eyes to the notion that what I had been taught were basic, simplified, industry rules and that we can actually logically understand espresso in more depth. It requires our time, some science and an open mind.
These old school rules have been proven to narrate less than the whole story. It is essential that they do not hinder development.
With speciality coffee, where roasting is focused on showcasing the flavours of a particular farm, blonding does not at all indicate that all the positive flavour has been extracted. This blond stream at the end of the shot can actually hold flavours that are the key to completing and balancing the cup.