Kohi Zeri, aka Coffee Jelly, is a popular summertime desert in Japan. Most Japanese desserts are nowhere near as sweet as the ones we're accustomed to here in the US; coffee jelly is simply a lightly sweetened, strong coffee, combined with agar agar to form a gelatin. Immensely popular, kohi zeri is sold in most restaurants in Japan as well as in almost every konbini (convenience store).
Agar agar, also known as kanten in Japan, is a great vegetarian substitute for gelatin, as it is made from an algae. Unlike gelatin, it does not need to bloom, and creates a firmer gel with a better bite texture. Agar agar is also used in panna cotta and can be substituted in equal quantities for gelatin. You can find agar agar in almost any health food stores; here in Birmingham I have seen it at both Organic Harvest as well as Whole Foods. However, it is also available at any Asian market, and is usually MUCH cheaper.
Agar agar also makes amazing Jello shots thanks to the firmer texture.
In addition to agar agar powder, stores may also carry agar agar flakes. I try to avoid the flakes, as the powder tends to dissolve MUCH better and gel better. Agar agar is also used in molecular gastronomy in place of sodium alginate to make mock caviar; I will be posting a tutorial on this very soon.
Coffee jelly is often served simply with a small spot of whipped cream on top, but is occasionally served with sweetened condensed milk on top as well. You could even try topping it with dulce de leche (shameless plug), mixing it in with iced coffee, or eating ith with ice cream (oooh). Oddly enough, I am not a coffee drinker, but I absolutely LOVE coffee jelly. It's the perfect dessert; easy and inexpensive to make, low in calories and sugar, and, without the whipped cream, completely fat-free.
Kohi Zeri / Coffee Jelly
2 cups strong coffee
2 Tbsp sugar
1 Tbsp agar agar powder (or unflavored gelatin)
4 Tbsp HOT or boiling water
First, brew 2 cups (16 oz) of strong black coffee. I prefer to brew mine with an Aeropress. Add the sugar to the coffee and stir until the sugar is completely dissolved.
Use whatever coffee you usually drink. For this batch, I used Dunkin Donuts' House Blend.
Next, combine the agar agar with the 4 Tbsp water, stirring until the powder is completely dissolved. Agar agar is a gel at room temperature, so the water needs to be very hot for the agar agar powder to dissolve. You can also use unflavored gelatin, but keep in mind that the jelly will not set as firm.
SLOWLY add the water when mixing the agar agar to prevent clumps.
Combine the agar agar mixture and the coffee in a saucepan. Heat over medium-low to medium heat just to a simmer, stirring well to make sure both the sugar and agar are dissolved. Simmer for 5 minutes, then pour the mixture into a shallow container. Gently smooth out any air bubbles with a rubber spatula.
Cool the mixture to room temperature; the agar will begin to set fairly quickly. Chill until completely cold and firm before serving. Cut the jelly into cubes if desired and serve with your preferred topping.
I have no idea why the liquid level looks so crooked in this picture...