Troubleshooting FAQ


Check below for answers to commonly asked questions

Does Immersion work with 14 gallon fermenters?

Immersion works best with 5-6 US gallon liquid volumes in fermenters with a capacity of 8 US gallons (30L) or less. 14 US gallon fermenters require custom insulation and enough liquid volume for the rod to touch the wort. While Immersion can work, performance is not guaranteed. We do not make jackets for 14 gallon fermenters, so insulating it yourself with a minimum of 3″ thick insulation is critically important.

Immersion is cooling or heating slowly

Immersion is a gentle cooler and heater that lowers and increases the temperature of your beer gradually over the course of a few days. Normal performance is 1ºF/hour for the first 10º F below/above ambient, 0.5º F/ hour for the next 10º F below/above ambient, and 0.25º F/ hour for the next 10 to 15º F below/above ambient. If your unit is cooling or heating slower than this or not at all, check below.

  • Heating with the Immersion must be done with yeast present in your fermenter. If you are performing a heating test with only water (without yeast), you will observe poor performance. This is because the Immersion was optimized to be used with yeast, and yeast activity produces a high convection circulation of the fluid inside of the fermenter. Without active yeast, the water being heated at the top would just get warm, while the water at the bottom of the fermenter would take much longer to warm up.
  • Check the ambient temperature of your room. If your room sees large swings in temperature, or generally increasing ambient temperatures, Immersion’s performance will be degraded. Both direct sunlight and lack of ventilation are two common causes of high ambient temperatures.
  • Let your jacket equalize in temperature for a few hours before you begin using Immersion. If the jacket is too warm, it will cause a startup lag as Immersion must cool both the wort and the jacket to the same temperature before it can make measurable progress on cooling the beer.
  • Make sure the temperature probe is plugged in tightly and is registering the correct temperature. Submerging into an ice bath should yield 33.6ºF / 0.9ºC. If your probe is not reading 33.6ºF / 0.9ºC in an ice bath, follow the instructions below to re-calibrate your probe. Taping your temperature probe to the fermenter in the upper 1/4 of the liquid level will ensure an even measurement.
  • Unscrew your rod and make sure nothing is between the cold contact point on the head unit and shiny surface of the rod. Obstructions here will inhibit heat transfer.
  • Turn on the unit, set it to cool. Wait between 5 and 10 minutes after the fan turns on and feel the air being released – it should be warm. If it is not warm at all or if it is very hot, contact
  • Make sure the heat exhaust vents aren’t blocked by the jacket.
  • Cinch the jacket tightly around the rod. A loose jacket can cause warm air to enter the insulated area and warm up the beer.
  • Feel the jacket insulation for gaps, both the around the body and around the base. If the insulation is not uniformly distributed around the fermenter, heat will be able to enter the fermenter.
  • More your fermenter to carpet or wood flooring or place a towel or blanket under your fermenter. Fermenting on cement or tile can allow heat to be transferred into the fermenter, hampering performance. Adding ground insulation can help performance.
Probe placement

Immersion Pro requires the probe be placed in the upper 1/4 of the liquid level, either taped to the outside of your fermenter or in a thermowell. This probe placement is very important while heating because the heat comes from the Immersion Pro unit which sits on the top of the fermenter. Since heat rises, keeping the probe on the top of the liquid level ensures your yeast stay at the correct temperature while the heat makes its way down the heat transfer rod.

For cooling, probe placement is less important for the very same reason. As heat rises, the beer will cool uniformly through the fermenter. However when the beer gets close to freezing, a slight gradient will form. When the system gets to 36° or 37° (2° – 3° C), the heat from a warm ambient environment will enter the jacket causing the beer near the outside of the fermenter to read slightly higher in temperature than the beer right next to the rod. At this point, yeast are no longer active and producing a convection flow giving way to the possibility for ice to form on the rod. If does ice form, heat transfer will be hampered as ice is an insulator. Your system will either stop decreasing the temperature or your probe may even read increases in temperature.

Therefore if you are attempting to get your fermenting beer down to freezing, we suggest using a thermowell as close to the rod as possible, or simply setting your Immersion to cool to just 37°. If you suspect ice has formed on your rod, we recommend unplugging your unit for at least 30 minutes. This will cause the rod to warm slightly and melt the ice around it.

Immersion is stuck at a particular temperature

If your unit cannot proceed past a certain temperature, try the following:

  • Make sure your Immersion is in a well ventilated room. The head unit exhausts temperatures in excess of 90º F while cooling and if that warm air gets trapped in an area where air does not easily exhaust (like a closet), it can increase the local temperature and greatly diminish cooling performance.
  • Monitor the swings in ambient temperature in the room that you are fermenting in. If your ambient temperature swings higher during the day and lower at night, the speed of cooling can be degraded. An average of the high and low ambient should be used to assess expectations of maximum temperature delta over ambient.
  • Take an internal temperature reading of the beer. Some fermenters are better insulators than others and the internal temperature may be slightly lower than the temperature being reported between the jacket and the fermenter’s wall. If you find this is the case, installation of a thermowell will yield more accurate readings. Be careful however of thermowell placement. Many stanard thermowells are lower than the recommended placement for accurate Immersion Pro temperature measurement.
  • Put the jacketed fermenter on top of a towel or blanket. Cement and tile floors can transfer heat into the fermenter and placing a layer between the floor and the fermenter can prevent this heat transfer from occurring. Carpet and wood are generally better insulators and don’t normally require additional insulation.
  • Check for breaks in the jacket insulation by pressing in along the body and the base. If you find a place that is not fully insulated, heat can enter your fermenter and remove the work Immersion is doing. Newer models of Immersion carboy/bucket jackets have a zipper on the base. Unzip your jacket and inspect your insulation for breaks. Fix as needed.
My rod looks worn. What happened?

A certain amount of wear is normal for rods. If you notice texture or color differences, you may need to condition your rod.

To condition a rod:

  1. Clean it with soap and water thoroughly
  2. Either place rod in oven at 250º F/ 120º C for 1 to 2 hours,
  3. Or boil the dark grey portion of the rod in deionized water for 1 to 2 hours.

Conditioning the rod will re-hydrate the anodized layer, creating an even passive layer that yeast, hops, and their acids will have a hard time reacting with and therefore penetrating.

Sometimes very strong acids (star-san) and bases (oxygen cleansers) can remove the protective layer if they are exposed to the rod for an extended period of time. Therefore we recommend only using Iodine based sanitizers and soap and water to clean. If the rod is heavily soiled, soak with soap and water and give the rod a good scrub. Make sure not to use anything too hard that would scratch the rod – the rod has a very hard coating, but it may still be scratched with very hard materials.

If there is no grey layer left on your rod, discontinue use and email

How do I sanitize the rod without using iodine?

The best way to sanitize your rod without iodine is to simply put it in the boil along with your wort for 30 minutes. Just be sure to unscrew your electronic head unit before doing so. You can also put the rod into the oven at 250º F / 120º C for a period of an hour.

Do not use acid or oxygen based sanitizers on the rod. These sanitizers have extreme pH values that can damage the rod’s finish if allowed to contact for a prolonged period of time.

My displays aren't lighting up
  • Verify there is a green light on the power supply. If no light, make sure all plugs are securely plugged in and you are using a functioning outlet.
  • If there is a green light on your power supply, unplug the head unit and plug back in.
  • If no lights return, email
My power supply is making noises

Some BrewJacket units were shipped with fanned power supply units and these fans can sometimes make noise as they age. If you hear a noise, email

How to calibrate your Immersion (Pro and single display models)

If you believe your Immersion (single display) or Immersion Pro is reading the wrong temperature, follow these steps to set it again:

  1. Press BrewJacket logo and + button. Your display will flash. You can press – or + to change the calibrated temperature.
  2. Press BrewJacket button to save the calibration.

If you need to revert to factory settings, first change the temp mode to F (press BrewJacket logo and the – button at the same time, press + or – to change to F, then press BrewJacket button again to save).

  1. Fill a cup up to the brim with ice then fill then fill the cup with cold water to the top of the ice level.
  2. Insert the probe into your ice bath and stir with the probe for 30 seconds, or until the temperature on your head unit stops changing.
  3. A factory calibrated head unit will read 33.4°. If your unit does not read 33.4°, calibrate the unit so it reads 33.4°.
How to calibrate your Immersion (dual display models)

For dual display Immersions only.

Fill a cup with ice to the top, then top off with cold water. Place your probe into the cup and stir with the probe for a minute or so. Your CURR temp should drop down to 32° F / 0­° C. If it does not, press both buttons down at the same time. SET will read 00. Now press up or down to change CURR. Press both buttons again to exit calibration mode and save the correct temperature.

If your probe is not responding to changes in temperature, email

Temperature reading jumps around excessively

If your temperature appears to jump around, unplug the temperature probe and plug it back in. If jumping still occurs, unplug the power cord and plug the power back in. If you still see jumping after that, email

I have a one, two, or three gallon fermenter. Will Immersion still work?

Immersion only works with fermenters that are 16″ in height or taller. Shorter fermenters with less liquid cause the fermenter to be top heavy and put it at risk of falling over. Therefore many small capacity fermenters are simply too small to function with Immersion. The only 3-gallon fermenter we have found works well is the 3-gallon Better Bottle.

I want to do a half sized batch - will Immersion still work?

Yes. With less liquid, there will be less submersion of the heat transfer rod, however this is okay since there is simply less liquid to cool. Half sized batches do work, however be aware of that your temperature probe may not read accurately outside of the fermenter and a thermowell may be required.

My Immersion is loud. Is there anything I can do?

Immersion registers a sound reading of 45db at 3′ away. This is roughly the sound of a soft conversation. The noise is the result of cutting air and forcing it down on to the heat sink. We currently do not have any ways to reduce this noise as this air flow is necessary for heat dissipation and adequate cooling.

If your power supply is the source of the noise, please email

I live outside of the USA - what should I expect?

Immersion ships with universal power supplies and compatible plugs for most countries in the world. When importing the device into your country, there are a number of things you must be aware of:


  • Customs duties
    • Many governments charge their citizens money to import goods into their country. This charge is separate from the postage that physically gets your device into the country. The UK for example charges 20% VAT, or Value Added Tax, to all goods imported of a certain class, of which BrewJacket Immersion falls into. There are no countries where Immersion is prohibited for import, however be sure to check with your local government for importation regulations.
  • Fermenter lids
    • The fermenters used in the USA and Canada are different from those used in Europe, Asia, and Oceana, and it is difficult for BrewJacket to carry stock of all lid varieties in the world. Therefore if you intend on using a fermentation bucket as your primary vessel for use with Immersion, you may need to drill its lid. Just one 1.75″ hole is required to fit Immersion’s rod. If you require air release, we sell a Blowoff Kit that requires an additional 0.5″ hole to be drilled.
  • Fermenter sizes
    • Immersion’s jacket can insulate fermenters up to 15″ in diameter and up to 22″ tall. If your fermenter does not fit into the jacket, your cooling performance will suffer greatly.