At Ferrell brewing Co we have just started using a  iSpindel to monitor how are fermentations are going. The iSpindle is an open source wifi enabled hydrometer but what the hell is a hydrometer. A hydrometer measures the relative density of liquids based on buoyancy and brewers use this to calculate how much sugar is left in the beer they are fermenting. 

Once we have finished brewing and have transferred the wort to the fermentor we will take a sample of the beer and cool it to 20oc and use a hydrometer to taking a reading. This reading is the Starting Gravity of SG of the  wort, It tells us how much sugar is in the wort and potetially how strong the beer might be when fully fermented.

Over the next few days the yeast will eat the sugar and turn it to alcohol and CO2. As brewers we would normally take samples every few days to see how fermentation is progressing. Fermentation is not complete till the yeast has eaten all the sugar it can. If we where to finish fermentation to early and package the beer with sugar that could still ferment in we risk overly carbonated beer that will fountain out of the bottle or can. This happened with our first brew of Manoro Mango IPA as the mango had additional sugar we had not accounted for. Hi “everyday is a school day”!

So when the hydrometer reading stop changing we know that fermentation has finished and we can cold crash the beer to drop the yeast out of suspension to give us a clearer beer. It also allows us to calculate the strength of the beer. By taking the Starting Gravity and subtracting the Final Gravity and applying a multiplier we can calculate the Alcohol by Volume or ABV. We need to do this so you know how strong the beer is and for beer sales to calculate the beer duty due on it.

So why is a wifi enabled hydrometer interesting or useful.

Well normally when monitoring how our fermentation is going we would normally have to take multiple readings. These samples need drawing, checking temperature and recording. This use about a 100ml of beer each time and takes time and effort. By having a wifi enabled hydrometer we can take a sample reading automatically every 5 minutes. When we see no change we know we have completly fermented. It also allows us to fine tune temperatures as the fermentation continues to the best out of the yeast we are using. It will also highlight any fermentation problems a couple of days sooner then we would normally see.

The ispindel is a open source digital hydrometer that use a 3 axis accelerometer to know what angle the iSpindel is floating at in the fermenting wort. By knowing that as the density of the wort changes the angle of the iSpindel will change and thus giving us our gravity reading.

Practically it allows us to know what is happening in the fermentor without disturbing it and without having anyone invloved in taking samples. As there is a temperture sensor on it as well we have a backup temperature reading for the fermentor should there be any problems with the fermentors temperature probe, which has happened in the past!