BBC Radio 5 Live Interview: "The Science of Coffee" with Josh Clarke, Dr. Chris and Naga Munchetty

Naga Munchetty (Host): We have got someone who knows a lot about different types of coffees, roasts and specific blends, Josh Clarke is a ‘Coffee Expert and Buyer’ for Coaltown Coffee Roasters, hello Josh.

Josh: Hey, how’s it going?

Naga Munchetty: Good, we’ve got two opposites here in the studio. Chris drinks 5 cups of coffee a day and sometimes a Turkish cup of coffee 9 o’clock at night.

Dr. Chris (Guest Expert): Hey, yes roughly 5-9 cups of coffee a day isn’t unusual for me

Naga Munchetty: We then also have myself who has decaf 99.9% of the time, very rarely do I have caffeine. Partly because it does nothing for me, it doesn’t suit me or my stomach. So, what’s a reasonable amount of coffee to drink Josh?

Josh: The reasonable amount is relative to each person, I’m a sort of 3 cup kind of person, 2-3 is about average but there is loads of research going into coffee at the moment. Just last week European Heart Journal with the University of Havard  published a study which compared the difference between morning coffee drinkers and afternoon coffee drinkers and the amount of consumption that went into it.

Dr. Chris: What about all day coffee drinkers like me Josh?

Josh: Well, this study didn’t look at all day for now, that’s probably where it’s going next.

Naga Munchetty: It’s because it’s not right.

Josh: There were health benefits associated. It said 16% of them had longevity of life, 31% had less chance of cardiovascular disease by drinking coffee in the morning. So, there are caffeine benefits. There are lots of other compounds in coffee that are really good for you as well, even if it doesn’t agree with you.

Naga Munchetty: Like which compounds are good?

Josh: Well there is some really fascinating assists in coffee, which are good for stomach ph or there is trigonelline which is good for you and has muscular skeletal benefits. It’s the compound that makes coffee taste sweet, that’s one of the things I like about coffee, the flavour and aromatic qualities in it. The caffeine topic is really interesting, do you guys know why caffeine is found in coffee?

Naga Munchetty: No

Dr. Chris: It’s basically a pesticide isn’t it, thats why we put it in with our plants, to rid of insects that are trying to eat them. But it is apparent that its edicts some pollinators. There are Bumble Bee equivalents of me, who are hooked on the flowers that make loads of caffeine.

Josh: This is a result of coffee that grows at slightly higher altitude as an example. Stereotypically it has less caffeine in it as they don’t need to produce the natural occurring pesticide in them as there are less insects eating them. There are lots of different components of it as well but stimulants, it seems to be the big effect that people talk about with coffee. I’m more into it for the sensory science.

Naga Munchetty: We’ve got some questions, here’s one for you first of all Josh. Wendy is asking, “We’re always being told that coffee is good for us but the caffeine content for different coffees is never explained. Is my cafetiere of two big scoops of ground coffee worth more than a mug of instant coffee? I’d love to know this, thank you.”

Josh: That’s a good question, I think instant has always got a bit of a bad rep but a cafetiere, it can depend based on the species of coffee. There are two main species, that we consume, Arabica and Robusta. Robusta is a bit more hardy (as the names suggests) and it grows at lower altitudes, therefore has a bit more caffeine. This stereotypically is used for instant coffee. So in that case, I would say that instant tends to have a ml bit more. A lot of that information can be found on food labels these days and on the high street, it does vary as well.

Naga Munchetty: Why does instant taste so bad, compared to fresh coffee?

Josh: Well I think everything we do to coffee is arguably detrimental. Coffee is the seed of a fruit, if we’re doing the best thing we possible can to the fruit, which is letting it ripen. If we then want to turn it into a coffee we drink, we have to strip it from its nutrient source, dry it, process it and ship it around the world. We then have to roast it at a ridiculously hot temperature and then grind it. But with instant coffee we’ve got to also freeze dry it and then package it, hoping when we pour hot water back on it, it still tastes nice.

Naga Munchetty: What do you expect, in other words? Chris this is for you, “Can you ask Chris, the effects of coffee on our cortisol in the morning, it brings on severe anxiety if I have it first thing?”

Dr. Chris: The way that caffeine affects us is that it actually potentiates the action of adrenaline and its chemical relative noradrenaline in the body. It does that because it inhibits a process that breaks down the signal that adrenaline makes in your cells. So when you produce adrenaline normally, that signals inside our cells. It gives us the livening affect, makes you energised, makes your pupils dilate, it makes you breath faster and affects your heart rate. That effect is reigned in by the break down of the single that adrenaline makes in the cells. Coffee and specifically the caffeine stops that breakdown process happening so quickly, so the adrenaline signal you’ve got lasts for longer. Therefore it will be higher and bigger, so you will have more energy, feel enlivened, you’ll feel more aroused as it were- that means that if your already anxious it will intensify anxiety. So, it’s chiefly potentiating your fight to flight reaction. The normal response we have when something frightens us and we prepare ourselves to run off or beat it to death.

Naga Munchetty: Yes, well that makes sense, thank you! Josh, when do you have your first cup of coffee, first thing?

Josh: I don’t tell many people this, I actually drink a cup of tea first in the morning but then I am straight onto coffee as soon as I get into the office, the batch brewer is always on ready. Part of my job is to taste, score and QC everything that comes out of our roastery as well, so I’m usually 2-3 cups deep by 8 o’clock.

Naga Munchetty: But tea has caffeine?

Josh: It does , yes and per gram, correct me if I’m wrong but tea has more caffeine it?

Dr. Chris: Yes it does, it’s interesting you mention the dosage. There was researchers in Scotland about 10 years ago, who were intrigued by what sort of dose of caffeine you get from a high street coffee. They did the experiment where they went round to different coffee outlets and bought an espresso and captured it into methanol cup to instantly freeze it. They then took it back to the lab and analysed how much caffeine was in there and it varied by 100’s of percent. So some outlets are giving you the equivalent of just one home-coffee-instant-dose, others had 3-5 times the amount of caffeine in it. So you get a very different hit from coffee outlets.

Naga Munchetty: Josh, how do you make the perfect cup of coffee, brew the perfect cup of coffee?

Josh: That’s a great question, this is where it’s really a science. I think the best way is to drink filter coffee, which is just coffee and water. I like the drip method because you are able to pour water over ground coffee and let it all extract through. And what you’re left with is a really delicious coffee. I think that’s the perfect way because there is no hiding place, no additives, it’s just coffee and water, the coffee has to do the talking. There are loads of ways to get it right but there are lots of ways to get coffee wrong.

Naga Munchetty: So just in a coffee machine, when you have a capsule, is that not good?

Josh: Capsules are good and they have their own place, it’s not my preference, just because of the strength of them. I think it’s 1 in 3 homes in the UK owns a capsule machine, they are super, super popular and they make consistent coffee. I think that is  definition of good coffee, is something that is consistent. You want your coffee to taste the same, time and time again if you hit the right flavour profile.

Dr. Chris: What we haven’t talked about much yet is the whole roasting process, cause that’s the real art isn’t it? You take the seed out of the middle of the fruit and you roast it to within an inch of its life and your affectively putting flavour in it, by burning it.

Josh: Yes, totally. So the roasting process, I use to think was really long, slow and not as hot as it is. It’s really hot, really fast. So round about 200 degrees is the ambient temperature of a roaster. The coffee is going through mallard reaction, so it’s just like when you put your bread in the toaster and you get toast. The browning process or the caramelisation process that takes part, is a chemical reaction because of the sugars that are in coffee, as it’s the seed of a fruit. So, during this roasting process is what gives coffee its aroma, flavour and its bitterness. All these volatile compounds, as they’re roasting, browning, caramelising, they are making this really complex sugar chain. Now us as roasters, what we’re trying to do is maximise sweetness in coffee. If coffee is not sweet, people want to do something with it, whether that’s milk or sugar or something along those lines. We’re trying to make sure we’re building on these complex chains, as a result giving you hopefully the most sweetest and consistent cup.

Naga Munchetty: You’ve changed someone’s life today you two, Brendan was the one asking about the anxiety Chris. He says, “Thanks Naga,  decaf for me now on.” Someone else has said they’ve been told by a neurologists they must change to decaf due to chronic migraines and says they are grieving it. It’s obviously the healthier thing to do.

Dr. Chris: Yes, migraines are a response of your blood vessels. It’s in the traction from your nervous system and blood vessels and how the two talk to each other, which produces the pain in your head. So yes, there are a range of triggers for migraines, chocolate includes similar compounds as coffee. So chocolate is a classic one but caffeine itself can do this.

Naga Munchetty: Josh do people judge your coffee when they come round yours for dinner?

Josh: Do you know embarrassingly, we very rarely end up with coffee in the house. My wife similarly is a bit sensitive to caffeine, so usually coffee is only at work for me. However we’ve just launched 3 decaf coffees, so they’ve been in the house a bit more recently and as a result I’ve been able to entertain and brew a bit more coffee, particularly over the Christmas period.

Naga Munchetty: Josh Clarke ‘Coffee Expert and Buyer’ for Coaltown Coffee Roaster, thank you so much and Chris it’s been a joy having you in the studio.