When iGulu Goes Beyond Brewing
A cold brew coffee experiment at home, exploring smooth extraction, gentle carbonation, and new flavor possibilities beyond traditional fermentation.
Cold brew is not fermented, but it still fits the iGulu spirit.
As iGulu continues to explore more beverage possibilities, our team started testing drinks that go beyond traditional fermentation. This time, we tried cold brew coffee.
Why it makes sense
Technically, cold brew coffee is not a fermented drink. But it still benefits from a low-temperature, sealed, and controlled environment. For iGulu, this makes cold brew an interesting test case beyond beer, kombucha, cider, and other fermented drinks.
The goal of the test
We wanted to create a cold brew coffee that feels smooth, well-integrated, refreshing, and flexible enough for different flavor variations.
A colder, smoother, more playful coffee experience.
Cold brew coffee is built around low-temperature, long-time extraction. Compared with hot coffee, cold brew usually has a smoother mouthfeel, lower perceived acidity, and a more rounded flavor profile.
Low-temperature extraction
Stable cooling helps support a cleaner and more refreshing extraction over a longer steeping period.
Smoother mouthfeel
The drink can feel softer and rounder than hot coffee, especially when using a low-acidity bean.
Light sparkling potential
With iGulu’s temperature control and pressure settings, cold brew becomes more than coffee steeped in water. It can move toward a lightly sparkling texture.
Dark roast, low acidity, and a fuller flavor base.
For this test, we chose a dark roast coffee bean with flavor notes of almond, dark chocolate, and roasted nuts. This profile works well for cold brew because it naturally leans toward a fuller and smoother flavor direction.
Why coarse grind matters
We used a coarser grind size than we normally would for faster extraction methods. A coarser grind helps slow down extraction during the long steeping time, reducing the risk of excessive bitterness and preserving a cleaner flavor structure.
Flavor direction
The almond, dark chocolate, and roasted nut notes came through in a more balanced and integrated way. Instead of chasing intensity, we wanted the drink to feel cohesive, smooth, and easy to enjoy.
Start with 1:10, then adjust by taste.
For first-time testing, 1:10 is a good starting point. It gives enough body without becoming too heavy.
A good starting point for body, smoothness, and drinkability.
A milder version with a softer coffee presence.
A more concentrated version for a deeper coffee flavor.
The process is simple, but a few details matter.
Keep the coffee grounds contained, use clean liquids, and give the drink enough time to extract smoothly.
Grind the coffee beans
Grind the coffee beans to a coarse particle size. For this test, we intentionally kept the grind on the coarser side to create a gentler extraction over the long steeping period and reduce the chance of the coffee becoming overly bitter.
Place the grounds in a filter bag or filter container
Put the ground coffee into a cloth filter bag and make sure it is properly sealed. Loose coffee grounds may enter the liquid and potentially clog the tubing or flow path. A cold brew filter container or filter carafe can also work, as long as it keeps the coffee particles contained.
Add the liquid
Pour room-temperature water into the machine, then place the prepared coffee bag inside. Besides the basic water version, we also tested two variations: replacing water with an equal amount of apple juice, and using a blend of apple juice and jasmine tea.
Set the machine
Use either CO2 Cooling Mode or Sparkling Water Mode. Let it sit for 18 to 24 hours. For a more noticeable sparkling texture, you can let it rest a little longer.
Softer, smoother, and more rounded than hot coffee.
After 18 to 24 hours, the cold brew is ready to drink. Because we used a dark roast, low-acidity coffee bean, the flavor leaned toward almond, dark chocolate, and roasted nut notes.
What we liked
Together with the coarser grind, the extraction stayed gentle and controlled. The final drink did not feel overly bitter or aggressive. Instead, it had a more complete, integrated, and smooth drinking experience.
The main takeaway
For us, the most important part was balance. Rather than simply chasing intensity, we wanted a cold brew that felt comfortable, refreshing, and easy to enjoy.
Changing the liquid changes the entire drink.
One of the most interesting parts of this experiment was replacing water with other liquids. The same basic process can lead to a completely different flavor expression.
Apple Juice Version
Replacing water with apple juice added natural fruit aroma and a soft sweetness. It made the coffee feel rounder and more playful, creating a more creative cold drink experience.
Apple Juice + Jasmine Tea Version
Adding jasmine tea to the apple juice brought another layer of aroma. Alongside the coffee’s nutty and dark chocolate notes, jasmine tea introduced a light floral character. The result felt more layered and unexpected, while still keeping coffee as the base.
What if cold brew coffee meets cider-style fermentation?
During the apple juice test, we found that while apple juice brought more fruit aroma and flavor complexity, its sweetness was also quite noticeable. That led to another idea for a future test: adding a yeast suitable for cider-style fermentation.
An experimental direction, not a final conclusion
In theory, fermentation may help consume some of the sugar, reduce the overall sweetness, and introduce new flavor changes. It may also open up the possibility of developing a certain level of alcohol, depending on the recipe and fermentation conditions. This idea has not been tested yet, but that is exactly what makes the process exciting.
Protect the machine and keep the liquid clean.
To make the process smoother and reduce the risk of clogging, keep these details in mind.
Make sure the coffee grounds are properly sealed in a filter bag or filter container. Loose particles may affect the flow path.
A coarser grind is better suited for this method. It helps control bitterness and keeps the long extraction process more stable.
If you use apple juice, tea, or any other flavored liquid, choose options without pulp, tea leaves, sediment, or visible particles.
iGulu’s beverage possibilities go beyond fermentation.
From beer and kombucha to cold brew coffee, sparkling coffee experiments, and other creative home drinks, iGulu is gradually becoming a platform for exploring more beverage styles at home. Some are fermented. Some are not. But they all point to the same idea: home beverage making can be more flexible, more creative, and more enjoyable
