From the Lab, Resources for Roasters

Monday, October 4, 2021

Roasting for Espresso: Part 2

Last week Joseph walked us through the basics of building an espresso blend. Now that we’ve crafted a brief, selected our components and roasted them individually, he’ll give us pointers on roasting, blending and brewing the best espresso blend.

This is Part 2 of Joseph's Roasting for Espresso series. You can check out Part 1 here. 

Blending: Ratio

When you have found the right profile for each component you will begin the ‘blend build’ stage. What percentage of each component will you use? I will commonly start at 50/50 for a 2-bean blend and adjust as required from there. The bonus is if you hit the target with the initial 50/50 blend you can drop the mic and exit stage left!

However, as many of you will have experienced, this perfect ratio can be elusive! If the overall profile is not yet achieved, you’ll need to adjust your ratio. I will always adjust components in 10% increments and up to 25%. Any adjustments of less than 10% and you probably need to ask yourself ‘is this really bringing a noted or necessary change?’. I have typically found ratios to commonly fall in the range of 50/50 to 70/30 range for 2-bean blends, and 33/33/33 or 50/25/25 for 3-bean blends. The same principle applies to 4-beans blends. Anything above 75-80% of a single component starts to beg the question of ‘Can I just offer this as a single origin?’ or 5% of a component in a 3 or 4 bean blend ‘does this bring notable value’?

Blending: Roast Tweaks

While you will have already achieved the optimum development of each component back in the development stage, you may find that when blended, 1 or more components doesn’t sit right in the blend. This can be by way of one overpowering another, conflicting flavors or by ‘muddying’ the profile somewhat. This is when you may need to consider minor tweaks to the roast profile of the components in question.

If you weren’t able to solve the issue by adjusting ratios you may need to adjust the development. For example, if I find the overall profile is ‘muddied’ e.g. I have 2 components both exhibiting strong body, I would look at the fruiter component (in this case, the Ethiopian Natural) and either reduce the development time ratio (shorten the total roast time) or lower the drop temp with the aim of reducing the body of this component while highlighting the acidity, fruit and sweet notes. Then when re-blending with the Brazil Natural I would achieve a more balanced overall blend profile with the fruiter notes of the Ethiopian and body forward notes of the Brazil. Adversely, you may find yourself in the opposite situation where both components are too acidic, fruity, sweet with not enough body, so you would look at increasing the development time ratio (lengthening the roast time) or increasing the drop temp slightly of the Brazil Natural to provide more body.

Blending: Solubility

A challenging and often less considered yet key factor in the blending stage is solubility. This can get complex, but can also be simplified. You need to ultimately aim for a similar solubility of each component, which I will explain why shortly.

When you were tasting each component separately as espresso, how did the extraction time vs grind settings compare? For example, you may have run a 1:2 espresso ratio (e.g. 18g in, 36g out) with an extraction time of 27-29 seconds for each component, but your grind settings were significantly different, meaning that one of your components was more (or less) soluble than the other.

If you have one component that is significantly more (or less) soluble than the other, the concern in this case is that when you blend and grind these together, one (or both) components will not be extracted optimally. This is where it can get complex. You need to look at each component and decide the best course of action. ‘Can I increase/decrease the drying, Maillard, development time ratio to increase or decrease the solubility for a particular component, while still achieving the desired flavor profile of the blend?’ Including, can I adjust the drop temperature to achieve the desired result?

To increase the development time ratio, you can simply extend the total roast time by a set amount (e.g. 10 sec) while still maintaining a nicely decreasing rate of rise. Adversely you can reduce your total roast time in order to reduce your development time ratio. You can also apply more heat in the early stages of the roast to increase heat penetration during the drying phase which will assist in increasing solubility. The opposite applies to reduce solubility, slightly less heat during the drying phase but this process can cause risk of lack of heat for the remainder of the roast. If you have too much heat you can reduce your input but lack of heat can be hard to add back in at certain stages of the roast.

To recap: always follow a clear product brief. If you need to go back and change your brief, that’s okay! Always taste your progress, involve your team, do blind tastings and don’t overcomplicate the process! Complex flavor doesn’t have to mean complicated! Adaptability is vital. Be inquisitive and try new things. Just because you have used the same Washed Colombian for the past 4 years doesn’t mean that you cannot change this for an equally expressive washed Papua New Guinea.

And finally, use us! Talk to your Trader, we can help you find what you are looking for.


Joseph Oosten, Trader with Sucafina Specialty New Zealand, has 12+ years of experience roasting in Australia and New Zealand. He started roasting in 2001 and has also operated his own cafe and served as a business consultant in the sector.