Not all extracts are created equal, and in cold drinks like this the flavor difference is obvious. [2] X Research source In the US, look for “vanilla extract” (or “vanilla flavor” for an alcohol-free option), and avoid “imitation vanilla. " In Europe, look for anything labeled “natural. " Most vanilla extracts from Latin America are inferior products, although often cheaper. [3] X Research source [4] X Research source

There may be some health concerns related to the “unbounded fructose” in inverted sugar. [8] X Research source Consider asking your doctor first if you have diabetes.

If you don’t have a candy thermometer, you might want to take the pan off the heat while the syrup is still clear or light brown, to prevent burning. The lighter the syrup is, the less caramel flavor the soda will have. Sugar syrup gets dangerously hot. Handle with care and keep away from children.

If you used a real vanilla bean, remove the pod and throw it away. If you dislike the seeds in your drink, strain the syrup through a cheesecloth. (Try it with the seeds first — many people don’t mind them, and the cheesecloth will soak up some of your syrup. ) Store extra syrup in the refrigerator. It will usually last at least a week. [11] X Research source

Since this soda is acidic, there is a chance that the dairy will curdle. Avoid this by pouring slowly and starting with chilled water. Lower-fat products (whole milk or skim milk) are more likely to curdle.

There is a chance of explosion from any home brewing. A plastic bottle is less sturdy (especially the bottle cap), but less dangerous if it does explode. A glass bottle from a brewing supply store is less likely to explode, but more dangerous. This is a very small batch compared to most brewing projects, which is good for a first timer who doesn’t want to waste ingredients on mishaps. If you’ve already done some home brewing, you can increase this to a larger batch.

You can use baker’s yeast in a pinch, but this is not recommended. You may end up with unpredictable amounts of carbonation, or a less pleasant flavor. You can skip the activation, but the soda will take longer to carbonate.

Leaving it at room temperature too long can generate enough pressure to explode the bottle! This is especially true at high temperature or if using old yeast.