The floating hydrometer (RAPT PILL, iSpindel etc.) is probably the best friend of the hobby brewer, allowing you to follow the progress of the fermentation on an up-to-date graph. It's very important to see the temperature and specific gravity trends. You can draw accurate conclusions. The product is a red capsule, if you use more than one RAPT it is easier to distinguish them. It is very easy to use, you can see how it works here. The device is calibrated. It's very small and compact. With a diameter of 37mm it fits in most fermenters. Thanks to the rounded design, it's harder to get Krausen on it and measures accurately. The measuring interval is adjustable, and with average use it will often last for years on a single charge. The Brewfather stores all previous fermentations, so if you try a strain of quaff at high and low temperatures, for example, you can see exactly the characteristics of the strain. It's also a big help when it comes to recipe reproducibility.
