Digital hydrometers are they it worth it?

So anyone that knows me, probably realises that I’m a bit of a geek for gadgets to brew with, I’m pretty inept at actually making stuff, but i’ll always give it a go if I can. I’ve made a temp control unit that works well and then recently I decided I wanted to make a DIY version of the TILT hydrometer called iSpindel, a recent post by @angelhomebrew prompted me to resurrect this post.

Also, Angel Homebrew have a nice little competition at the moment to win a 50L Brew Devil all in one brew system, so even if you don’t read this post any further take a look at the competition and then check out the shiny stuff on their website (I can thoroughly recommend the weldless ball valves) –

I’ve been ermming and arrghing over whether to make this post a how-to, but whilst I can probably provide some pointers (ask away in the comments) there are many people on the web much better skilled than me who can provide you with the information, so I’ll signpost instead.

Effectively what TILT and iSpindel are gyroscopes in a testtube that change angle based on the density of the wort, some clever maths following a simple calibration run and you can convert this to gravity points.

It’s pretty hassle free and instead of taking regular 100ml samples from your wort you can just log onto a (free) logging website and check your beer My iSpindel readout although it is still a good idea to taste your beer as you go along, but you don’t need to draw as much out in terms of samples.

(if my graph isn’t working or it’s just. flatline I’m either not brewing anything or have just finished brewing.) but it would look something like this (you can tweek or adjust as you like)


I’ve been using iSpindel now for a few beers and following my calibration it’s pretty accurate, to within 0.001 gravity points (from what I’ve seen) I’ve not had any issues with infections using it, battery life is really good and I found it pretty simple to set up using the guides detailed at the end of the post.

I really like the ability to view how my beer is fermenting remotely, either from work or from the comfort of my sofa, it’s convenient, iSpindel lets me monitor temperature and Plato/Gravity and I’ll definitely keep using it for brewing.  Even more so as the temp control method I use will be integrating iSpindel in the near future.

I’ve not used TILT before so can’t do a direct comparison in terms of functionality. Popularity, however, suggests that they’re good and work well. They also come in different colours. So if you fancy finding more about TILT and remotely logging your brews head over to Angelbrew and take a look.

If however, you’re a skinflint like me or like building your own projects then it really is something that anyone with a bit of confidence can do.  If you’ve not soldered before I’ve made a little PCB that you can buy from the states (4 for around £5.60) which means you just slot the components into the corresponding holes flip over and solder in, so no long trailing wires or anything like that (Nope I don’t and haven’t made any money from it).

So are these digital hydrometers worth it, from my limited experience I’d say yes they are, my iSpindel will last a couple of months in an FV before the battery konks out, you don’t need to keep taking samples if you don’t want to, and if you don’t have temperature control, it will at least log the temp of your wort so you can see how the yeast is working.  If I had a bigger brewing budget I’d consider buying a TILT, the iPhone app sounds interesting, and the fact it’s pre-calibrated would make life a little easier.

Yes it might be a step too far for some peoples brewing but I think the fact there are people working on integrating things like TILT and iSpindel into Temp control systems (see Fermentrack and Brewpiless) where the temp reading on the hydrometer can prompter your chamber to heat or cool, which I think is a great step in terms of fermentation monitoring.

So, in short, should you get one, yeah I think if you can afford it buy one, and if you like tinkering go ahead and try and make one, just don’t hold Macc Homebrew responsible if it all goes wrong.

So you want to build an iSpindel

As mentioned I’m not going to do a guide I’ll signpost, but I have provided some info on the forum  if you want to build it yourself here is the list you need, you might want to shop around and see if you can find it cheaper and the most expensive part I found was the sled to hold it all in place in the test tube

So what will you need. (along with links to the relevant Aliexpress Wishlist)

  • Soldering iron and solder (but it’s not too complicated a job.
  • ESP8266 Board
  • Gyroscope – GY-521 MPU-6050 MPU6050 Sensor Module
  • Battery charger thing – 5V – 1A Micro USB 18650 Lithium Battery Charging Board Charger
  • Some resistors – 4.7k, 220k and 470ohm
  • Toy switch
  • Rechargeable Battery – 18650 D1 3000mAh Li-ion 3.7v
  • A sled to hold all that in
  • Test tube
  • some wire
  • Optional circuit board.

When I purchased all my parts separately it came to around £30 and was pretty fiddly as I had to cut up my own circuit board to solder (it was a real mess) which lead me to build my own circuit board.  Tjorben from 3D-mechatronics contacted me and asked if he could use the board in packs that he is selling, which in exchange for a few sleds I agreed to.  The pack sold is linked here and has a great guide in terms of how to solder it all up and if I were to make an iSpindel from scratch this is a really convenient place to get your stuff, for the sake of a few quid (and not having to solder direct to a battery)

iSpindel Set

if you really want to scout around for a bargain and are happy to wait for shipping, Aliexpress is your best bet all the components you need are here – Aliexpress you will needs some wire to solder it all together if you choose not to get the PCB though and a tiny square PCB breadboard too.

But if you want to buy bits individually, perhaps because you want to make more than one.

Aliexpress all the components  – 17.02

PCB Board – – £5.60

Sled – – £12.50

TestTube – – £2.20

Wheel balancing weights – to help make sure the tilt angel is correct.

so the total for one board would equate to around £40 if bought separately, less if you can 3d print your own sled.

Given the amount of components you’ll have spare if you buy from aliepxress though, If you made 4 however it would come down to around £30 each (nearly 1/2 the price of this build is the sled so if you can find someone to print it)

Once you got everything ordered and in one place you then need to flash the Wemos and then wire it all together.

To make life a little easier flash your Wemos first, what this basically means is that you put the software on the Wemos which is the brain of this project. But in doing it before you make an adjustment to the Wemos ESP8266 means that you only need a USB mini cable.

Firmware Release flash – PC instructions

-Install Wemos driver
-Download and start NodeMCU-Flasher
-Download newest release of / bin folder
-On the “Config Tab” select the .bin file by clicking on the gear
-On the “Operations Tab” a COM Port to the Wemos should show if the drivers are installed correctly
-Click on “Flash” and you will see the progress bar start moving

Next step wiring up

Again Tjorban has provided a very thorough guide to wiring everything up here – Downloadable PDF when removing the capacitors this can be done with wirecutters easily.

if you’ve decided to do it all from scratch, here is the link to the original information. – iSpindel GitHub 

It’s worth reading the whole thread first, and planning on where things are going to go then just do it, there really isn’t a great deal that can go wrong.

Once it’s all wired in,

In terms of calibration, you need to create a wort at the top end of your brewing scale and then track the gravity against the angle, the iSpindel Github link provides you with an excel document you plug everything into.  My method was to brew a big Dopple bock and through in the tilt and brew a beer with it, so effectively my first brew with iSpindel was a calibration brew.

As usual any comments or questions drop a line in the comments below, and I’ll try and answer them.

Other useful links –  this includes pictures of my first attempt at soldering up a blank board, you can see why I choose to then build my PCB.

2 thoughts on “Digital hydrometers are they it worth it?

  1. I’m currently in the process of building an iSpindel to partner with my BrewPiLess and as my soldering skills are basic your PCB has made life so much easier than using stripboard (and makes it look far more professional). Thank you so much for sharing it.

    All my soldering is done. I just need to add a switch (considering using a reed switch and wireless charging to avoid opening the case) and then get a petling and a sled to fit. It is good to hear that you are happy with yours.

  2. Yeah really happy with it, where are you based I probably have hundreds of those little switching knocking around if you want one. Drop me a message via twitter or Facebook and I’ll post one out to you if in the UK. I’m tempted with wireless charging but Still think I’ll need to remove the lid to clean properly, so glued my sled in so things don’t really move.

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