Advanced Coffee Making

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ACM Real World Applications

ACM 7.01 – Roast Solubility

Roast Solubility

When profiling coffee, you are comparing multiple test roasts with regard to their sensory properties; at the cupping table, we find it very helpful to use a cupping protocol that gives each cup identical brewing parameters, including a precise crust-breaking (stirring) method. After stirring, we remove a sample from each cup after exactly the same amount of time. After completing our sensory assessments, we compare the TDS measurements to get an idea of which brew’s profile is more soluble.

BH Roast Profiling Approach Using Solubility

For example, let’s say you have four test roasts and you taste them and test their TDS after eight minutes, samples drawn from the cupping bowls four minutes after you break the crust.

For roasted coffee, the desired product is a delicious tasting roast that is highly soluble. If the coffee is delicious and has a low solubility, that’s fine, but it costs your customers more money to brew with as they will have to use more coffee to achieve their TDS targets than they would need using a highly soluble roast. They won’t thank you. Differences like this are exaggerated in espresso coffee so, as great tasting cupping bowls with low solubility usually indicate, you will have a difficult time reaching 18–22% extractions when brewing this same coffee as espresso.


TEST #1: One profile gives you a TDS of 1.5% but tastes burnt, so it’s no good. That’s a win for solubility but a loss for flavour — we’ll forget that one.

SolubilityFlavour ❌

TEST #2: The next sample profile tastes very vegetal and has low solubility. This is definitely no good.

SolubilityFlavour ❌

TEST #3: the next one tastes delicious and has a TDS of 1.15%

Solubility 1/2 ✔Flavour ✔

TEST #4: the profile after that tastes delicious and has a TDS of 1.3%

SolubilityFlavour ✔

The obvious choice of profile to give to your customers is the final roast with a 1.3% TDS.