I recently read a chain of discussion around roasting styles that I found really interesting – “Nordic” style roasting vs underdeveloped roasting”. This touches on a trend in roasting which involves the lighter style of roasting that we see in some café’s. It is said about this style, that the coffee has barely left the first crack, that the last phase can last for about 1.5 to 2 minutes. For some reason, this is a trendy thing with the ‘hipster-doofus’ crowd (not my words).
‘Nordic’ style would be around “light-Medium” or “city”. We at Cirelli Coffee tend to roast around “Medium-High”.
Now, I’m going to start off with a little conspiracy theory to this argument. There are some that say this trend is driven by maximising the roasters profits!!!! Shock Horror. How you may ask?
Well, quite simply, as you roast you lose natural moisture that is trapped in your bean. Your roasted coffee will naturally weighs less the darker you roast. So the lighter you roast, the more your beans will weigh.
On average you can lose between 15-25% depending on your roast. So if you multiply that over 1000’s and 1000’s of kg it can amount to quite a lot of money lost via simple evaporation.
In addition, a lighter roast often needs a double shot to give you that same coffee taste and hit…OMG…I hear it again…”Cha-Ching”…Is that another boost to the roasters profit ? So if you can convince your café and end patrons that a lighter roast is better, then that equates to an immediate boost to your profits. Hang-on is this also why the standard basket sizes have increased? “Cha-Ching” and hang-on is this why café are also pushing smaller 6OZ cups sizes…STOP, STOP…”Cha-Ching”…Is this a trend driven by taste or profits…Hmmm, this is getting a little too controversial. At the very least, something to think about.
Putting those terrible conspiracy theories aside, I now turn to explaining the roast and simple coffee roasting science.
As each roast of coffee develops it will go through two distinct changes, generally characterised as 1st and 2nd crack. At each stage whilst you roast, you will hear the beans cracking as they expand. Similar to corn popping when roasting popcorn.
Some of these changes are visible and some not so visible. All aid in giving characteristics to the coffee.
• Colour changes (bean absorbs heat changing from green to a yellowish / then yellow / then light brown / then brown and dark brown exposing the oils.)
• Growth of the bean during roasting: as water moisture evaporates the beans fracture (1st and 2nd crack) releasing enormous amounts of energy. The bean will almost double in size.
• Shrink can be recognized to be between 15% and 25% depending on the roast level.
• Chaff (silver skin) flaking off the bean (before the first crack)
• Release of natural oils onto bean exterior after roasting. If the coffee is roasted dark even more oils are exposed.
Non visible physical and sugar development changes during roasting
• Moisture loss (shrinkage)
• Sugar Browning and Maillard Reaction
Lighter roasts are generally stopped shortly after first crack and can often give you a “lemon” or ”brighter” taste in your cup. Some will argue that you’re getting more of the original taste of the coffee. Now, there is nothing wrong with the lighter roasting but there is a vast difference between a properly developed light roast, and a roast that is simply cut short without any development time. This can be nearly as unpalatable as over roasted coffee. However, simply cutting 4 or 5 minutes off of your roast doesn’t make it a good lighter roast. You have to understand profile development first, and then tackle the nuances of a proper light roast.
Now light roasts may taste good for some but I like to use the example of browning onions on the BBQ to explain some differences. When you brown onions on a BBQ you will get some people that like crispy onions…goodness some eat them raw like apples. Nice and crunchy. Yummmmo….BUT this is not for me. Something special happens when the onion starts to brown. The skin softens, the moisture is released and the onion cells start to breakdown. The natural flavours and sugars within the onion begin to caramelise. At this point you get a light sweetness that is distinctly different than the raw taste you might experience when they are still raw. If you leave the onions cooking, they get to a point where they will char and turn black, crispy and lose that sweetness. They taste nothing like onions.
This is similar when you roast coffee. This caramelisation is the result of a ‘Maillard’ reaction that occurs in a roast. With coffee, this is a chemical reaction between amino acids, peptides and proteins which react with reducing sugars that caramelise, that gives coffee the desirable flavour, sweetness and aroma. Too much caramelisation can result in the sugars completely becoming charred giving a bitter taste.
Apart from coffee and onions, the Maillard reaction is responsible for many colours and flavours in foods:
• The browning of various meats like steak, when seared and grilled.
• Toast and the darkened crust of baked goods like pretzels and bread.
• The golden-brown colour of French fries.
• Malted barley, found in malt whiskey or beer.
• Dried or condensed milk.
If you don’t control this ‘Maillard’ reaction you could end up with a mouth puckering coffee even if it’s meant to be everything but mouth puckering (lemony taste and that’s about it). There are many ways to reach your end goal or the perfect roast. What we strive for is a certain roast time. 1 to 2 minutes (give or take) can make a big difference as can a fast roast and a slow roast. I believe that some development of the roast after 1st crack is required. This must involve a stable but gradual rise in temperature (3-4 minutes) rather than rising too quickly (some coffees have almost no interval between first and second crack). If your development time is too short it will result in an underdeveloped coffee. Alternatively, if your development time is too aggressive you risk over drying and charring the cellulose structure within the coffee.
So ladies and gentlemen, it’s important to control your Maillard reaction rather than to letting fashion trends turn your approach.
Personally, as mainly an espresso drinker I could never understand the appeal of “lighter” roasted coffee…and hopefully it’s a trend that will go away once people realise what they’ve been missing.
Cirelli Coffee – The coffee people are talking about…