Nath Prosser, Managing Director of Heartland Coffee Roasters in North Wales, has shared some of his tips for producing the perfect coffee every time.
Being front and centre of a thriving coffee roastery means having the confidence to innovate and take a risk – something Nath Prosser embraces wholeheartedly.
Now the Managing Director of Heartland Coffee, North Wales’ leading coffee roastery, Nath has helped shape a journey of continuous exploration and discovery in the world of coffee.
Heartland's story began when founders Mal and Tara moved from New Zealand to the UK in 2000, bringing with them a love of - and expectation for - quality coffee. Spotting a gap in the market, they started roasting beans at home and later expanded to London’s Greenwich Market. Fast forward to today and they’ve moved their operation to North Wales and employed a full team of staff led by Nath, all of whom continue to drive their passion for exceptional coffee.
With a focus on discovering new flavours, sourcing unique coffee origins, and experimenting with different roast profiles and brewing techniques, they aim to raise people’s expectations of coffee.
Below, Nath shares some insights gained from years in the roasting industry - from key roasting techniques to practical advice for home roasters:
1) Always be led by taste
It sounds simple, but this would be one of my key pieces of advice. It’s very easy to become distracted with new roasting techniques and trends. But at the end of the day, the taste dictates the success of a coffee.
2) Don’t get swept up by internet trends
With that in mind, I’d urge you not to get stuck on trends. If you go online and start to read about roasting and what you should be doing, you'll probably see lots of examples of roast heat curve graphs. But in reality, every roasting machine is different and no two brands behave in exactly the same way. It’s unlikely they’ll look and behave exactly the same as another roaster’s experience.
Take a roaster’s probe, for example. Depending on placement and size, each one will detect heat at different stages. If the probe is higher up the wall of the roaster, for example, the coffee is going to be less densely packed together than it is at the bottom, due to the drum rotation and keeping the beans moving around inside. That means there's going to be more space and therefore more air, which will give a higher temp reading than if the probe is lower down in the drum.
It's all about learning what temperature and duration creates the perfect taste for you. It really is trial and error with your roaster.
We like to stay true to our principles, whilst keeping an eye on innovations in methods. Take the recent trend around supremely light roasted coffee… it got to the point that the coffee could be just undeveloped. I've had some disappointing coffee experiences because of the lightness of the roast. For us, we always say: ‘Right, just taste this thing. Would we want to drink it?’ Having that level of honesty and a self-critical view is critical, in my opinion. We want to retain the origin character, whilst developing the coffee well, aiming to create a coffee that shows the best of itself and gives the best experience. It’s all just our take on that though, roasteries are all so unique.
3) Work from the first crack
The golden rule, regardless of your roaster or temperature probe, is simple: whatever temperature you get at first crack, you work from that. Don’t just follow a temperature guide that you’ve seen online.
For example, if a guide suggests reaching first crack at 195°C and finishing at 205°C or 207°C, simply add 10 degrees to the temperature you see on your roaster at first crack to achieve a similar outcome.
4) Be as consistent as possible and plan your stock and orders in advance
One thing we've learned in the coffee world is that consistency is crucial - not only in delivery but also in roast level and flavour. Well, as much as you can manage due to the seasonal nature of coffee beans anyway.
Planning ahead is important. Try to anticipate demand and order green beans well in advance. We typically secure our green bean contracts a year ahead to lock in prices and ensure we know what to expect, roughly when to expect it, and can therefore offer fair, transparent pricing to our customers.
When ordering, fill up your pallets - we know they’re not cheap - by bringing in as much stock as possible per pallet, while considering your storage capacity and anticipated demand. You don't want to disappoint customers by running out of stock.
If I was going to share a resilience tip, avoid single points of failure in your business and aim to keep at least a month's worth of green beans in, based on your forecasts. The coffee market can be volatile, and disruptions like shipping delays - such as ships stuck in the Red Sea - are not uncommon these days. Having a backup stock ensures you can continue operations smoothly during unexpected delays.
5) Be transparent and trustworthy with your pricing
At Heartland, we aim to offer a fair margin. This means that whether we're selling a £7.60 bag or a £20 bag, the amount we make is the same. If we used a percentage-based approach, the price of the £20 bag would become much higher, making it unaffordable for many customers.
This strategy helps us stay sustainable as a business, allowing us to pay bills, pay staff, keep moving forward and be able to buy more coffee and grow.
6) Be sustainable where you can
Our commitment to sustainability began many years ago when we formed our first direct relationship with a Honduran farmer. We bought his entire crop, and we've continued to do so every year for the past 15 years.
Since then, we've established many more partnerships and added a variety of coffees to our lineup. For example, we source single-family Brazil coffees that serve as a versatile all-rounder in terms of flavour. By increasing our order volume each year from the producer, we strengthen our relationship and ensure mutual success.
We've also invested in fully compostable packaging. Although it was a significant investment, we believe it's worthwhile and helps differentiate us as a business committed to sustainability.
7) Look at origin and altitude
I actually very infrequently look at the tasting notes that are given from my green suppliers. Instead, I focus on variety, species, altitude and country of origin.
It’s important to remember that density and altitude are intertwined, while origin can impact both. From there, you can determine a starting point for how you're going to roast each coffee.
8) Experiment with YOUR roasting machine
Whenever I tell people in the roasting world what we do with our landmark blend, they'll say: ‘Seriously, how does that work?’ There's loads of assumptions about how it must taste. But the taste comes from the way we set up the roast, the way that our roasting machines work, and how we take the beans through that journey – we love to roast manually ensuring each roast has had the required attention to give the most consistency and quality.
When roasting our house espresso, we pre-blend rather than post-blend, using beans which are all of a similar grade from South and Central America. Then, as each of them has a different origin, it means they’ll have a different density and moisture content, so we can manipulate the airflow and burner intensity throughout the roast to compliment each one of them.
9) Find your ‘Goldilocks Zone’
There are so many parts of the roasting process you can experiment with and adapt depending on your taste and desired outcome – from pre-heat temperature to drum speed, roaster type and duration.
Generally, the higher the drum speed, the shorter the roast time. The key I’d say is looking for that ‘Goldilocks zone’ – where everything aligns, starting temperature, drum speed, airflow… they all need to line up to give you a great roast.
As a basic guide to start you off, I’d say you're probably looking at a roast in and around 9 to 10 minutes long. And if you can have say 9 minutes pre-first crack, plus anywhere from 40 to 60 seconds following that first crack, you’ll be doing well. Ending temperature is of course variable depending on your roasting machine.
I guess our roasting philosophy is to represent the coffee's origin and its characteristics – you want to ensure the roast and flavour stays true to those. Also, try and make each coffee as accessible as possible if you’re running a roastery. As I mentioned at the start, this is about raising people’s expectations of coffee.
