All basic functions necessary for the measurement are included in the free version of the Brew Meister for EasyDens app. Therefore, a subscription is not mandatory.
Subscription to full access will make handling more comfortable and might be more tailored to your needs. Especially if you use the EasyDens on a regular basis, full access to provided functions might be helpful in daily business.
Do not hesitate to subscribe and get full access for free for the first year to try the premium functions.