> For the complete documentation index, see [llms.txt](https://docs.brewfather.app/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.brewfather.app/integrations/ispindel/calibration.md).

# Calibration

Boil 3 liters of water with 1 kg of sugar to begin with.\
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Use a hydrometer to work out and create solutions of **1.050**, **1.040**, **1.030**, **1.020**, **1.010**, and finally clean water at **1.000**.\
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Configure the iSpindel to report every 60 seconds into Brewfather. From the devices page, you can then read the current value every minute. Start by reading the angle in SG 1.000 and, if needed, adjust the weight to give a starting angle of around 25 degrees.\
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After reading and recording all angles in the different solutions, fill in the values in the calibration spreadsheet for the iSpindel project, and it will calculate the formula based on your unit.\
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Copy the formula into your Polynomial under Configuration and start reading the values in the different solutions again. Plato is Brewfather's default iSpindel interpretation, and Brewfather converts Plato to SG for display and logging. If you use a formula that outputs SG directly, wait until the device has logged once, then open the batch's **Fermentation > Readings > Devices** list and set the iSpindel gravity-unit button to **SG**. The old **\[SG]** name suffix is still supported as a legacy fallback.

If you are using Plato in Brewfather for the SG solutions above you should see values close to 0, 2.5, 5, 7.5, 10 and 12.5 Plato matching the correct SG.

#### Resources

Excel calibration sheet: <https://github.com/universam1/iSpindel/blob/master/docs/Kalibrierung_en.xlsm>

More info: <https://github.com/universam1/iSpindel/blob/master/docs/Calibration_en.md#formula>\
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## Related docs

* [iSpindel Setup](/integrations/ispindel.md)
* [Devices](/devices.md)


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