Start Cooking

Combustion Inc App Basics

Using your Predictive Thermometer without a Display? Go here. Otherwise, read on.

1. Charge the devices

Charge the Predictive Thermometer (20 min) and the Display (90 min). Use USB-C (cable included).

Collapsible content

Thermometer power basics (important)

The Predictive Thermometer turns on when you remove it from its charger.

There are 4 possible power states:


When you take it out of the charger, the thermometer starts in "instant-read" mode. That’s the highest level of power consumption, because it’s transmitting data the most frequently. In this mode, the expected battery life is 5.7hrs. 


When you set a “cooking to” target temp (step 4), the thermometer will change from instant read to cooking mode. With a full charge, the expected battery life while cooking is 24 hrs. 


When the thermometer is in the charger, it enters “standby.” You can be sure it’s in standby if the Display is not showing a temp. In standby, the expected battery life is 14 days. If your thermometer has been in standby for more than a week, it’s a good idea to “top off” the battery with a quick 5-min charge before starting any long cooks. 


The thermometer is only charging when it’s in the charger and the charger is plugged into USB-C power. (There is no battery in the charger.) 

Red light = charging 

Green light = fully charged (or thermometer not detected) 

No light = thermometer not detected (or charger not plugged in)

Charging details

Predictive Thermometer: 

Snug the thermometer into its included charger. 

Plug in the included USB-C cable and any USB-C power supply.

The charger light will glow only when the charger is plugged in. 

Red light = charging 

Green light = fully charged (or thermometer not detected) 

No light = thermometer not detected (or charger not plugged in)

Always store the thermometer in its charger. After one minute, it will go into “standby” mode. 

In standby, the thermometer battery will last 2 weeks before needing a recharge. Even so, it’s never a bad idea to “top it up” by charging for 5 min before cooking.

⚠︎ : The Combustion Display will show a warning emoji (triangle with exclamation point) when the thermometer’s battery is low. The warning first appears when there is 1 hour of charge remaining.

Display timer: 

Turns on when you press start/stop. Powers off when you hold start/stop (you’ll see the Display go blank).

Charges from any USB-C cable and power supply in 80-90min (from empty). 

When charging, the screen will display a blinking battery indicator. The indicator stops blinking when fully charged.

Battery life is 1 week of combined active use. This can vary depending on the number of connected thermometers and how much you use the backlight.

When not in use, the display will remain charged for 6-8 weeks.

1b. Update the firmware

The first time you use it, download the "Combustion Inc" app from the App Store for iOS or Google Play for Android. Open the settings menu inside the app, then click "update" for each device.

Collapsible content

Firmware update "how-to" iOS (Apple)

For best results, update your firmware (that's the software inside the Predictive Thermometer and Display).

You'll need the "Combustion Inc." app on a mobile device (iPhone or iPad) to apply firmware updates. (Get it from the App Store.)

Here are some step-by-step instructions for those of you who like them. (And just in case it doesn’t go perfectly, some troubleshooting steps below.)

For iOS (Apple devices)

1. Search "combustion inc" on the App Store (iOS).

2. Click "get"

3. Click "install" (wait for it to finish)

4. Click "open"

5. Remove your fully charged thermometer from the charger. Place your mobile device very near your thermometer (within a few inches). 

6. Click the fire icon (Combustion Inc logo)

7. Click "update" in the top area (thermometer)

8. Wait about a minute until it says "up to date"

9. Put your thermometer back in the charger and move it away from your mobile device. 

10. Turn on the Display (press start), and put it near your mobile device.

11. Repeat steps 6-8 for the display 

12. Nice work! Your firmware is now up to date

13. Recharge the thermometer before use

14. Press “cancel” to close out of the update screen and return to the main menu 

(Note: if you have more than one thermometer, repeat steps 5-8 one at a time for each.)

Troubleshooting firmware updates:

If the app (or display) doesn’t detect or connect to the thermometer, that usually means the Predictive Thermometer isn’t fully charged. Charge it for a full 20 min (or until the light on the charger turns green).

Don’t update more than one tool at a time – this can cause the app to get stuck. (That’s why the instructions have you powering on one Combustion device at a time.) 

If the update gets stuck or fails to complete, restart your mobile device (yes, that’s a pain, sorry about that). Restarting clears the Bluetooth cache. After you restart, update one device at a time as described above.

If that doesn’t solve the issue, please let us know.

Firmware update "how-to" Android (Google Play)

The Full Combustion Inc. Predictive Thermometer Companion app is now available.


Please update the firmware on your tools one at a time

(i.e. Do the Predictive Thermometer first, then the Display).

Please note: this is really not as complex as it looks; this instruction set is just very thorough; just in case. Don’t panic.


1. Search "combustion inc" on Google Play - select the "Combustion Inc" app (not the “updater” app)

2. Tap “install”

3. Tap "open"

4. Allow permissions

5. Remove your fully charged thermometer from the charger. Place your mobile device very near your thermometer (within a few inches). 

6. Tap the Combustion logo (fire icon) in the upper corner

7. Select the tool you want to update (thermometer)

8. Tap “update”

9. Wait about a minute until it says "up-to-date"

10. Put your thermometer back in the charger and move it away from your mobile device. 

11. Press “start” on the Display (to turn it on)

12. Repeat steps 6-9

13. Your tools are now updated! (They should show “up-to-date” and v1.1.0)

14. If you have another thermometer, turn off your other tools (hold “start” on the Display), remove the 2nd thermometer from its charger, then repeat steps 6-9

15. That’s it!

If the update does not complete, close the app and re-open it. If it says "updated" next to the tool listing (e.g. thermometer name), you're good.

2. Link the devices

• Turn on the display by pressing the Start/Stop button.

• Turn on thermometer by removing it from the charger.

• Place thermometer next to display for a few seconds. When a temperature appears on-screen, that means they’re linked.

(Note: you don’t need to repeat this process, the display remembers.)

Collapsible content

Linking details: multiple thermometers

The Display can be associated with up to 4 Predictive Thermometers simultaneously

For multiple thermometers:

Link one at a time.

After linking, put the first thermometer back into its charger. Place the second one next to the display.

In a few seconds you will see a number 2 next to the thermometer icon. In the future, this specific thermometer will be remembered as 2 by the display. Repeat this process for additional thermometers.

Pressing the temp button will cycle between output screens for linked thermometers.

Shortcut: hold a thermometer close to the display and it will prioritize displaying that specific thermometer.

To unlink all thermometers from the Display, do a full reset:

Hold light and start/stop for 1 second at the same time.

This will unlink all thermometers and reset all display preferences.

Linking troubles

If your Display is not detecting or linking to your Predictive Thermometer, that almost always means the thermometer battery is low.

Try again after recharging (20 min or until the charger light turns from red to green).

3. Insert the thermometer

Insert the Predictive Thermometer into the food. Be sure it’s at least as deep as the minimum insertion line (the three stripes halfway down).

WARNING: Don’t measure things hotter than boiling!

Keep the lower half below 212°F (100°C) at all times.  Higher temps can cook the electronics, and the brainy part is down near the tip.

It’s safe inside food because the water in the food keeps everything below boiling. Science!

The top half of the thermometer is built for high temps up to 570°F (300°C).

Avoid direct flame! Flare-ups can easily exceed temperature limits. The ceramic handle will provide brief protection, but not for long.

  • line art showing minimum insertion lines

    Be sure the minimum insertion line is inside the food.

4. Set target temperature

Press m- and s+ buttons to set the cooking to temperature for your desired doneness.

Wait 3 seconds, the "cooking to" temp will stop blinking. That means it's set.

Put the food in your oven, smoker, grill, frying pan… you get the idea.

(Hold temp for 1 sec to toggle between Cº and Fº)

  • Illustration showing location of plus and minus buttons for setting target temperature

Collapsible content

Predictive cooking details

The Prediction Engine’s initial countdown is usually within 10% of the true cooking time. It will adjust and become more stable as cooking continues.

Flipping food and changing the cooking temp will change the speed of cooking and the countdown prediction will adjust accordingly.

We recommend setting the cooking to temperature a few degrees below your ideal doneness. Stop cooking when the timer goes off, and watch the display.  Carve or slice the meat when the core temp reaches your target temp. This halts carryover cooking, ensuring perfect doneness!

Soon the Prediction Engine will be able to fully calculate and manage carryover cooking (we need more data to make it happen). That’s useful for some specific foods, but in general we don’t recommend prolonged resting.

Contrary to tradition, science shows that resting your meat doesn’t improve juiciness. It mainly results in cooler food and less crusty crust.

What about sous vide?

For the moment (and this could change rapidly) we can't recommend using the thermometer in sous vide.

We have to re-evaluate the vacuum-resistance (and thus sous vide readiness) of the main seal.

Don't fret! We think it's going to be fine, we're just not 100% sure at the moment, so we're doing some extra-strenuous testing. News on that soon.

5. Relax

The display will show progress by indicating % of cooking completed.

About a third of the way in, a countdown will appear: time to cook. That’s the magic number!

When that number hits 00:00, an alarm will sound to let you know your food is ready.

Collapsible content

What about low and slow?

What about low-and-slow? Until the surface temp is above the user’s target doneness, there's no point making a prediction because it's impossible for the core to get hotter than the surface. At a low temp, a slow cook will “stall” before the surface temp exceeds the target.

In practice this means it’ll happily keep an eye on your meat for as long as it takes to break the stall, then make a prediction and sound the alarm when it hits your target temp.

From there it’s up to you. Watch the surface temp and fine-tune your heat to hold that temp for as long as your super-secret recipe calls for.

We’re working on a method for predicting the temp and duration of the stall. It’ll take some time to finish, but the results will be worth the wait.

6. Clean up and store

Wipe your Predictive Thermometer with a soapy sponge. Dry with a dishcloth.

Soaking is ok. The Predictive Thermometer is rated IP68, waterproof to 1 meter for an extended period of time (over 30 minutes). That also means it's dishwasher safe.

For baked-on stuff, use an abrasive cleaning pad (we use steel wool) to scrub the ceramic handle.

Store your clean and dry thermometer in its charger. It will go into low-power standby mode and will hold a usable charge for about 14 days. Use USB-C to recharge (10 min).

Wipe the display with a damp cloth. Use mild cleaning products if necessary, nothing scratchy.


    Always insert to at least the minimum insertion line.


    You can check a simmer, but keep the pointy end out of things that are much above 212ºF (100ºC). No candy, boiling oil, molten gold, etc.


    The Predictive Thermometer is rated IP68 - waterproof to more than one meter. Dishwasher safe!

Collapsible content

More watchouts

Never cook with the thermometer inserted to less than the minimum insertion line.

Never use the thermometer to take an instant read for things significantly hotter than boiling water including deep fryer oil or candy.

Do not use the Predictive Thermometer in a pressure cooker, Instapot, broaster, or microwave.

Do not submerge a hot thermometer into cold water. The shock can crack the handle and cause the seals to fail.

Be careful with open flame. Flare-ups can often exceed the handle's max temperature rating (575ºF/300ºC). Prolonged exposure to direct flame can damage the main seal.

Don't use the Predictive Thermometer in sous vide (at least for now, we're investigating). The negative pressure (vacuum) may distort the main seal.

Other modes

Cycle through other modes (for up to 4 thermometers) by pressing the temp or time buttons on top of the display.

The temp button will cycle through displaying Core/Instant Read, Surface, or Ambient temperatures for each active thermometer.

The time button will set the display in kitchen timer mode. 

Instant Read Mode

When the thermometer turns on, it always starts in Instant Read mode.

If you need to take an instant read (for hamburgers or bread dough or a million other reasons), it’s always there for you.

Instant Read takes about 3-4 seconds to accurately report the temperature at the pointy end of the thermometer. The mode turns itself off when you set a cooking to target temp.

You will see the Instant Read glyph before that (if the handle sensor is below 130ºF (55ºC).

Note: Instant Read consumes more power (about 7 hrs total battery life) compared to cooking mode (30 hrs battery life). 

Surface Temperature Mode

During cooking, the Predictive Thermometer automatically locates the sensor inside the food that’s closest to the surface. This is the true cooking temperature your food is experiencing.

Press Temp to change mode from Core to Surface.  For sous-vide like results, adjust the heat level in your smoker or oven to keep the displayed surface temp at your ideal doneness temp.

Ambient Temperature Mode

The ambient sensor is the one that most accurately reflects the surrounding cooking temp (usually the handle sensor - t8).

Press Temp to toggle from Core to Surface to Ambient mode.

Don't be surprised if it's much lower than you expected. Your oven might say it's 400ºF (200ºC), but near your food the temp is much lower. Water, evaporating from your food, is only around 212ºF (100ºC). That steam actually cools the nearby air.

You can speed up cooking by starting hotter. Watch the ambient temp and when it’s where you like it, turn the heat down to your usual setting.

Kitchen Timer Mode

Naturally the Combustion Display also functions as a simple kitchen timer—smart products don’t always need to show off.

Press time on the top of the display to enter timer mode.

Press m/+ or s/– to set a countdown timer (up to 24 hrs).

Press start/stop to begin or pause the countdown.

Press m/+ and & s/– at once to reset.

Advanced settings

For a full list of Display controls and alerts, scroll to the bottom of the page.

Clear cooking prediction (temp mode)

Press m- and s+ at the same time. 

Clear countdown (timer mode)

Press m- and s+ at the same time. 

Clear temperature alarm

Press start/stop.

Switch between ºC and ºF

Hold temp for 1 second to toggle between American (ºF) and science-units (ºC).

Turn on tenths of a degree

While in temp mode, press m- and temp simultaneously.

Change backlight brightness

Press and hold the backlight button (center button on top of display). The backlight will turn on and then cycle through different brightness levels. Release the button when the backlight is at your preferred brightness.

Unlink all associated thermometers

Do a factory reset (below).

Factory reset

Hold light and start/stop for 1 second simultaneously to erase all settings and forget associated thermometers.

Mobile Apps

Apps are available for Android and iOS.

Download links in the footer (or search "Combustion Inc" in the App Store or on Google Play).

You’ll need to install the app in order to update the firmware (on-board software) of your thermometer and display.

Firmware updates improve the performance of basic functions (for instance, cooking predictions & battery life). They can also unlock new, advanced cooking features. 

We’ve kept our starter apps as simple as possible for ease-of-use. But we will be adding some very cool features as we go.

Apps will soon let you see, track, and export your cooking data so you can fine-tune your techniques.

You will also be able to rename each of your Predictive Thermometers for easier identification mid-cook. Yes!

Troubleshooting: firmware update

A few people have run into trouble during the firmware update process. Here's what to do if that happens to you.

The app (or display) doesn’t detect or connect to the thermometer? Usually that means the Predictive Thermometer isn’t fully charged. Charge it for a full 20 min (or until the light on the charger turns green).

Don’t update more than one tool at a time. This can cause the app to get stuck. Turn on only one Combustion device at a time when updating.

What if the firmware update gets stuck or fails to complete? First, try closing and re-opening the app. If that doesn't help, reboot/restart your mobile device (yes, that’s a pain, sorry about that). Restarting clears the Bluetooth cache. After you restart, update one device at a time as described above.

If that doesn’t solve the issue, please let us know. 

Troubleshooting: hardware

Until you update the firmware on your set, you may see some unusual behavior under certain cooking conditions.

Occasional erratic countdowns (happens when the prediction changes mid-cook, usually during reverse-sear)

Low battery life during low-and-slow cooking

Unstable display of instant-read temps

Detailed notes, bug fixes, and planned features are available on our product release notes page.

Troubleshooting: red alert

“The Display turned RED and started BEEPING and FLASHING. Why?”

Bad things can happen when you exceed safe operating temps. The "red alert" is a warning that your thermometer is in the danger zone. 


> 105ºC (sensors below the min line aka "pointy end")

> 300ºC (sensors above the min line aka "handle")

If you get a red alert:

1) Immediately remove food from heat

2) Check temps on Display - see if any reading (core, surface, ambient) is near or above the temp limits

3) Check insertion: is it at least to the min line? Was any of the lower part (below the min-line) visible (not inside the food)? 

If the lower sensors have exceeded safe operating temp, the electronics may have been damaged. If the thermometer is still broadcasting (the technical term is "advertising" temps) – if you're seeing temps on your display, it's probably ok. 

Follow these steps if a lower sensor overheat happened:

  • Confirm that the thermometer is still connecting to the display (temps are showing/updating)
  • Look for any erratic changes or strange temp readings (that would indicate a damaged sensor)
  • If you can’t connect or see erratic temps, contact support 
  • Otherwise the thermometer should continue to work normally   

If the higher sensors (handle end) have exceeded safe operating temp, it's possible the high heat has damaged the main seal (inside the handle). Your thermometer will most likely still work properly, if you follow some extra precautions.

Follow these precautions after a handle-overheat red alert:

  • Hand-wash only
  • Do not immerse/submerge the thermometer when cooking or washing

The risk is that the seal is damaged, which may allow fluid into the interior, which can eventually cause the internal electronics to short-circuit. 

Damage to the seal is cumulative. The first overheating incident may or may not damage it, but the more times it happens (and the longer it stays overheated), the more likely it is that water-resistance is compromised. There is also no way to inspect the seals for their integrity. 

Exceeding safe operating temperatures voids the warranty. If you have more questions, please contact support.

Upcoming features

The most important functions of the Predictive Thermometer are software-controlled. (There’s a teensy computer in there, FYI.)

Updating the onboard software (aka firmware) will improve the everyday performance of all the basic stuff. It can also unlock new, advanced cooking features. It’s like a free upgrade to your entire set.

To get firmware updates, you’ll need the mobile app. Once you’ve got that, we’ve made it ludicrously simple to update your devices (really; press “yes” to an onscreen prompt and your work is done). With the app, you’ll be notified as soon as new firmware is available.

The Dec 2022 update included:

• Better instant read response time

• More accurate Predictive Engine

• Longer battery life

• More robust surface temp detection

For spring 2023 we’re working on sophisticated new features including:

• Carry-over cooking predictions

• Stall predictions for low-and-slow

• Improved range/signal strength

More details on the latest and upcoming releases here.

Service & support

Visit the FAQ

If you're confused, try the FAQ first. It's possible someone else had that same question.

Questions about cooking with the Predictive Thermometer?

For more specific questions, check the subreddit (r/combustion_inc). Chris (our owner/resident expert on everything cooking-related) reads every post and often responds personally.

You also get the bonus of community expertise. Frankly, there are some pretty amazing and friendly cooks on there who may have the same questions and/or already figured out the answers.

Other issues?


If there's a problem or defect with your Predictive Thermometer, Predictive Timer, or the Combustion App, we're here to help.

We stand behind our stuff and will do whatever we can to make it right.

  • Illustration of location of time, light, and temp buttons on Combustion Display, plus how to turn on color backlight.

Display controls


start/stop Power on
hold start/stop Power off

hold m – (+) start/stop (for 10 sec)

Reboot display

TEMP mode

temp Temperature mode
m – (or) s + Set target temperature
m – (+) s + Clear target temperature
hold temp 1 sec Toggle °F / °C

TIME mode

time Timer mode
m – Add minutes
s + Add seconds
m – (+) s + Clear timer
start/stop Start countdown/up


light Backlight on/off
hold light Adjust backlight brightness
m – (+) light Starts cycling backlight color options. Press any key to select a color.
Display battery low
Thermometer connected
Thermometer battery low

blinking alert icon with red backlight and urgent beeping

Thermometer over max temp limit!

hold light 

(+) start/stop

Factory reset