When using the RAPT pill please be mindful that your reading can be off for the following reasons:
- High krausen
As the active bubbles that are hitting the hydrometer will put the reding off while you have this very high activity. So you can expect that this would effect the results. Similarly if you have a sample of beer in your conventional hydrometer that is full of carbonation this also puts the readings off as bubbles get stuck on the glass too.
- Stratification
If you drop in a large amount of sugar or water you can get some stratification if it's just sitting in place. For instance if you put in a fresh wort kit and then top up with water it's likely the water is sitting on top and thus if the pill is floating in the higher concentration of water at the top the reading will be off. If you shake up the fermenter vigorously it will generally fix this and give you a more homogenous mix.
- Incorrectly Calibrated
If you have not calibrated the unit we would recommend doing this. If you do the housing up to a different tightness then this can also put off the calibration slightly. In my opinion this is one of the major reasons to move to the wifi charger. If you get the wifi charger then you never have to open the housing and for that reason you also never have to calibrate again.
- Dry hops
If you add dry hops into the fermenter they will look like this for a few days:
View attachment 123827
As you can imaging no floating hydrometer is going to read this type of situation well.
- Dry crud on the hydrometer
If you have had active fermentation then dry crud sticks to the top of the pill hydrometer. If this stays on the surface of the pill it will typically look like the gravity is higher than it actually is. The simply solution is to shake the fermenter every now and then after high krausen and this will generally wash the chunks off the pill and allow them to sink to the bottom of the fermenter.
So basically if you shake the fermenter a few times and ensure it's properly calibrated you should get quite accurate readings at the end of the fermentation once the fermentation has slowed down.