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Given that you're fermenting in buckets, then you need a straight-walled thermowell, like this: enter image description here

You put the thermowell through the lid of the bucket and down into the beer. The temperature probe slides inside the thermowell.

The tricky part is to then make an airtight seal with the bucket lid. You can either buy a stopper with a hole, or a grommet. The thermowell goes through the middle hole of the stopper or grommet. Both will require that you drill a larger hole into the lid of the bucket. The OD of the thermowell is 3/8", so this is the size of the hole in the stopper/grommet hole you need. TheOnce inserted into the lid, the stopper/grommet will make an airtight seal both with the bucket and with the thermowell.

Given that you're fermenting in buckets, then you need a straight-walled thermowell, like this: enter image description here

You put the thermowell through the lid of the bucket and down into the beer. The temperature probe slides inside the thermowell.

The tricky part is to then make an airtight seal with the bucket lid. You can either buy a stopper with a hole, or a grommet. Both will require that you drill a hole into the lid of the bucket. The OD of the thermowell is 3/8", so this is the size of the stopper/grommet hole you need. The stopper/grommet will make an airtight seal with the bucket and with the thermowell.

Given that you're fermenting in buckets, then you need a straight-walled thermowell, like this: enter image description here

You put the thermowell through the lid of the bucket and down into the beer. The temperature probe slides inside the thermowell.

The tricky part is to then make an airtight seal with the bucket lid. You can either buy a stopper with a hole, or a grommet. The thermowell goes through the middle hole of the stopper or grommet. Both will require that you drill a larger hole into the lid of the bucket. The OD of the thermowell is 3/8", so this is the size of the hole in the stopper/grommet. Once inserted into the lid, the stopper/grommet will make an airtight seal both with the bucket and with the thermowell.

1
source | link

Given that you're fermenting in buckets, then you need a straight-walled thermowell, like this: enter image description here

You put the thermowell through the lid of the bucket and down into the beer. The temperature probe slides inside the thermowell.

The tricky part is to then make an airtight seal with the bucket lid. You can either buy a stopper with a hole, or a grommet. Both will require that you drill a hole into the lid of the bucket. The OD of the thermowell is 3/8", so this is the size of the stopper/grommet hole you need. The stopper/grommet will make an airtight seal with the bucket and with the thermowell.