What is the Tilt Hydrometer?
In a nutshell, the Tilt Hydrometer is a small plastic tube with electronics inside it for measuring the temperature and gravity of a fermenting beer. It can transmit those readings outside the fermenter (including stainless steel fermenters) via Bluetooth to an Android, iOS, or Raspberry Pi device.
The Tilt measures the gravity of your beer by the angle at which the device floats in the beer. The sensor inside the Tilt is a "military grade" sensor that is extremely sensitive.
The Tilt is powered by a replaceable (and inexpensive) battery that will last a few months, depending on the frequency of use.
If you want to use multiple Tilt devices, the manufacturer offers several different colored devices. Each color is registered differently by the iOS/Android/Pi application and tracked separately from the other colors. This allows you to place (for instance) a red Tilt inside an ESB, a blue Tilt inside an IPA, and a yellow Tilt inside a Belgian Dubbel while still tracking each beer's fermentation individually.
How Do You Use the Tilt Hydrometer?
When you are ready to pitch your yeast into a beer, sanitize the Tilt using Star San or Everclear, and drop it right into the beer. It will begin collecting temperature and gravity readings, which it will transmit via Bluetooth to any device running the Tilt application. An inexpensive and convenient option is to setup a Raspberry Pi with the Tilt Pi software from the vendor's web site and place the Pi near your fermenters.
What Information Do I Get from the Tilt?
The "Peach" line at the top is a user-defined name for this particular beer. Setting this name is optional but can help you keep track of multiple beers you may have in progress. (I often have 2-3 going so this is a valuable feature for me.)
You then see a "View Cloud Log" link. If you configure the Tilt application to log its readings to the cloud, this link will be present. It will take you to a Google Sheets spreadsheet where the data is automatically posted every 15 minutes. That allows you to see and track your fermentation from outside your home network if you like. Note that this means leaving a device with Internet access (a phone, tablet, or Pi) in the vicinity of the fermenters, so that it can grab the readings from the Tilt and post them to the Internet.
Below the big red bar, you see the "uncalibrated" gravity reading in smaller print and the calibrated reading (which are the same in this particular case) in large print. On the app, this is updated every few seconds. On the cloud spreadsheet, it's updated every 15 minutes (or at some other user-configured interval).
Below the gravity, you see the uncalibrated temperature and the calibrated temperature (in this case they are the same).
Below that in very fine print, you see the current date and time, the last time the app received a reading from that particular sensor, and the signal strength from the Tilt (which is another way to gauge the battery life).
Earlier, I mentioned that the Tilt software can optionally log fermentation data to Google Sheets. If you choose to do this, a Google Sheets spreadsheet is automatically created for you and updated as new readings are recorded. The sheet has three tabs of information.
The first tab (Report) shows you the overall status of your fermentation:
This gives a quick overview of your fermentation over time. In the example above, you can see that my beer went into the fermenter on December 2, 2018, around 6:30pm. The original gravity at the start of fermentation (the "High" figure) was 1.073 SG. The current reading is 1.018 SG. That current reading represents an apparent attenuation of 75.34% and an ABV of 7.22%. You can also see that the temperature has ranged from a low of 64F to a high of 72.4F, and is currently 70F.
The second tab (Chart) provides a graphical overview of the fermentation:
In the above chart, the blue line represents the gravity of the beer over time. We see it beginning in the range of 1.073 SG and working its way down to the current 1.017 SG range. You can also see that I raised the fermentation temperature from 64 to 72F to help encourage the yeast to produce some esters I wanted.
The last tab (Data) contains the raw data points captured by the Tilt. You can add comments there to indicate things you want to make note of (like adding fermentables, changing fermentation temperatures, etc.).
Is the Tilt Accurate?
That said, it's important to make sure that you calibrate the device when you change the battery. This is easily done by dropping the device in a glass of water and letting it "settle in". From there, you can compare the readings it provides of gravity (which should be 1.000 SG in plain water) and temperature (comparing to an accurate thermometer). You can use these to adjust the Tilt's reported values within the application or the Raspberry Pi GUI:
To adjust the calibration, select the color of the Tilt you're calibrating from the left-hand drop-down. Enter the correct SG value and the uncalibrated value for gravity. Do the same for temperature if needed. From there, the Tilt will automatically log and report the corrected (and uncalibrated) values.
|Changing the Tilt's Time Zone|
|Changing the unit types that Tilt records and displays|
|Filtering out weaker Tilt signals if needed|
All of this makes the Tilt an accurate way to monitor your fermentation gravity and temperatures without having to open your fermenter or extract wort from it.
The Tilt has allowed me to gain insight into how various yeast strains work. Its constant tracking of gravity and temperature helps me to see how long it takes a particular strain to start fermenting, gauge how active the fermentation is at any given point, and determine if I might need to rouse the yeast, raise the temperature, etc.
It's helping me in another important way, too. In the past, I would either have to guess when the fermentation was finished, or take samples out of the fermenter and test the gravity to see if it was changing from day to day. That guesswork is gone with the Tilt. I can look at the readings over a period of days to see if the gravity has stopped dropping. If so, I know fermentation is finished and it's time to cold-crash and/or bottle.
In practice, I've gotten about 3-4 months of life out of the batteries in the devices. If you brew less often, you might get more. I was able to buy a dozen replacement batteries for a few bucks. Replacing the batteries is a bit of a challenge, in that the cap(s) that are screwed into the ends of the Tilt's outer shell are incredibly tightly screwed on from the factory. Once removed, the circuit board is also pretty snug inside the tube, so you have to take care to push it out with enough strength to get it out of the tube, but not so much that you break the plastic parts inside. That said, I think it maybe took me 10 minutes to change the batteries in three Tilts and recalibrate them, so this is a pretty minor nit in the grand scheme of things.
My only other issue is with the Tilt Pi software itself. About every 3 months or so, it seems to develop issues. It stops logging the readings to the cloud, either for brief periods of time or it just stops altogether. Rebooting the device doesn't seem to make much difference. In the end, I find that the simplest solution is to just wipe and reimage the micro SD card and reconfigure it for my WiFi. Again, this is a pretty minor nit to pick, but it can be frustrating at time.
Is the Tilt helping me brew better beer? That's a little harder to say. It's certainly helping me reduce the number of overcarbonated beers I bottle. I think in the past I would assume that fermentation was complete when it wasn't, then prime the beer, bottle it, and find weeks later that the beer was massively overcarbonated. In fact, in a competition, that fact (plus the fact that I'd laid the bottles on their side while conditioning) cost me some points. The judge thought the residue on the side of the bottle indicated that I hadn't cleaned it thoroughly (not the case) and that the overcarbonation was due to an infection (and not over-priming).
Overall, I find the Tilt to be a very useful and fun home brewing gadget. It's helping me understand yeast better, keep an eye on temperature control, and better gauge when fermentation has actually finished. If you can afford one or more (they're around $130 each), I'd definitely recommend it.