In terms of flavor, it actually works well – adding just a subtle "walnut" flavor to your cuppa. However, like most "fresh nut milk," if you drink very strong coffee, the milk may split/separate (due to the high acidity). To try to avoid separation, you can pour the milk into your mug first and slowly top it up with the coffee. That way, it will help to temper the milk and (hopefully) prevent separation. However, in general, store-bought options are usually best for coffee, thanks to the addition of stabilizers.