Recipe: Coffee Soda by James Hoffmann
I. Recipe Development and Ingredients
The final recipe (available on the speaker's website) is the result of testing different base coffees, dilution levels, and flavour additions.
| Component | Specification | Rationale/Notes |
|---|---|---|
| Coffee Base | Espresso (Diluted) | Provides a clean, intense coffee flavor. Filter coffee was tested but espresso was preferred. The speaker recommends a clean, washed coffee that is sweet and delicious. |
| Sweetener | 2:1 Simple Syrup | A 2:1 ratio (2 parts sugar to 1 part water) is used to avoid excessive dilution of the coffee. Final sugar percentage aims for a moderate sweetness. |
| Flavour Add-in | Chocolate Bitters | Used to round out the flavours, soften them up, and provide a nice amount of bitterness and a chocolaty finish. The Angostura brand bitters were preferred over others. |
| Flavor Enhancer | Saline Solution (Salt Water) | A simple 20% salt solution (20g salt to 80g water). A tiny amount enhances flavour complexity without tasting salty. |
II. The Crucial Clarification Step
The most important step for a good coffee soda is clarifying the espresso:
- Problem: Espresso contains suspended material and fine particles that cause bad carbonation by providing "nucleation points," which make the soda too fizzy, frothy, and problematic.
- Solution: The espresso must be paper filtered (clarified) to get rid of the crema and suspended material.
- Method: Pour the espresso through an un-rinsed V60 paper filter. You must be patient, as the fines will often clog the filter.
III. Carbonation Technique
Successful carbonation requires the liquid to be cold and free of air:
- Chill: The liquid needs to be cooled down to around 2°C (35.6°F), as this is the peak temperature for water to dissolve carbon dioxide (CO2).
- De-Air: Decant the mixture into a plastic bottle and squeeze out as much air as possible before carbonating.
- Carbonate: The speaker uses a high-pressure CO2 rig but notes you can use a SodaStream or a creme whipper with CO2 cartridges.
- CO2 Level: The recipe aims for a medium level of carbonation, about 3 grams of CO2 per litre, resulting in a pleasantly fizzy, sparkling drink that avoids the "angry" or harsh carbonation of highly carbonated beverages.
IV. Final Assessment
The finished product is described as a fresh soda with a pleasant citrus aroma from the bitters, a nice coffee hit, and a delicious, sweet, and balanced taste. It is not designed to be shelf-stable and should be consumed quickly to avoid developing a sour, unpleasant taste.