Inkbird Dual Stage Temperature Controller ITC-308S with NTC Probe Review (2026)

What it does

The ITC-308S is a dual stage temperature controller built for fermentation and cold storage setups where a single unit needs to manage both heating and cooling. Home brewers commonly use it to control a chest freezer or fridge for fermentation chamber temperature, plugging a cooling appliance into one outlet and a heating source such as a brew belt or seedling mat into the other. The controller reads the actual liquid or ambient temperature from its probe rather than relying on the appliance's own thermostat, which keeps fermentation temperature far steadier than a stock fridge dial ever manages on its own.

Sensor and accuracy

This model uses an NTC probe, the same sensor family used across Inkbird's ITC-308 line, and Inkbird's published specifications for the ITC-308S list a 2 meter cable length with a temperature resolution of 0.1 degrees and an accuracy rating of plus or minus 1 degree Celsius across most of its working range. That resolution is tight enough to hold a fermentation chamber within a degree or two of a target temperature, which matters for yeast strains that throw off flavors when they run too warm. The probe is a plug-in design, so a damaged or lost sensor can be replaced without discarding the whole controller.

Power handling

Inkbird's listed specifications for the ITC-308S put the maximum load at 10 amps across a 100 to 240 volt AC input, which covers a typical mini fridge or chest freezer paired with a lower draw heating device without tripping the unit. The controller body measures roughly 140 by 68 by 33 millimeters with a separate socket housing around 85 by 42 by 24 millimeters, so it sits as a compact inline box between the wall outlet and the appliances rather than a rack mounted unit. Brewers running larger commercial cooling equipment should still check its individual amperage draw against that 10 amp ceiling before relying on this controller.

Fit for homebrew fermentation control

The dual outlet layout is exactly what most fermentation chamber builds need, since a single controller can flip a fridge compressor on when the probe reads too warm and switch on a heat source when it reads too cool, holding a tight band around a set temperature. This is the same core approach that made the original ITC-308 popular in the homebrew and kegerator community, and the ITC-308S carries that reputation forward with its updated probe hardware. Buyers should still budget for the fridge or freezer, insulation and any heat source separately, since the controller only handles the switching logic rather than the appliances themselves.

Value and trade-offs

Against other dual stage controllers on the market, the ITC-308S benefits from Inkbird's long track record in the homebrew and reef keeping space, where the platform is widely documented and easy to find replacement probes and wiring diagrams for. The listing does not spell out cable length for the outlet cords themselves, so brewers with a fermentation chamber set up away from a wall outlet may need an extension cord or to plan cabinet placement carefully. Overall it is a straightforward, well supported way to add real temperature control to a fermentation setup that would otherwise depend on ambient room temperature alone.

Frequently asked questions