Measuring Up : Calibrating The Fermenter To Monitor Efficiency

I’ve recently calibrated my fermentation bucket so I can see how much wort and beer I’m actually getting from each batch. This quick guide shows how I did it.

beer fermenting bucket

Why Calibrate The Fermenter?

In case you’re wondering, I’m doing this as part of my ongoing investigation into improving my home brew process.

I’ve conducted experiments with mash efficiency and have realised that my liquid measures are fairly haphazard, and are limiting my ability to track quantities and adjust recipes.

Improvement in this area will let me repeat and refine beers that turn out well.

At each stage in the process I loose fairly large quantities of liquid, going from 21 litres at the start of mash to only 12 – 14 litres making it as far as the bottles.

Although I’m not too bothered by the actual numbers, I am keen to know where the losses take place so I can alter recipes to take them into account.

How I Set Up My Measuring Fermenter

I started with my blank-faced white bucket.

When full it contains 20 litres, but apart from that it’s pretty difficult to gage the level of beer. It’s possible to see the beer line through the plastic, which is slightly translucent, so a readable scale on the outside of the fermenter is feasible.

Using my measuring jug I added water in fixed increments.

Litres are my measure of choice but take whatever you think will be most useful: pints, quarts, gallons, whatever.

Fill the fermenter in small steps so that future measurements will be reasonably precise, to the nearest litre for example.

measuring jug pouring water into a home brew fermenter

After each litre was added, I marked the water line on the outside of the bucket. Masking tape was useful for this.

light through beer fermenter

Depending on your lighting conditions you may need to use a torch to exaggerate the shadow of the water. Otherwise the difference in colour between water and air is fairly subtle!

Continue filling the bucket in steady increments, marking off each step as you go.

home brew fermenter with markings up to 6 litres

If your fermenter is completely cylindrical you could extrapolate the scale along the bucket with a ruler, after measuring the depth of 1 litre (or other measurement).

However, because my bucket tapers away from the bottom I decided to use water to manually measure everything.

beer fermenter and measuring jug

I stopped when I reached 16l, which I seldom exceed when brewing. Do whatever is going to help you with your own process and stop at that.

calibrated beer fermenter

I also plan to calibrate my brew pot with volume markers, so I can check how much water is lost during the boil and when I remove hop debris.

Eventually I’ll have a clearer picture of what happens to my wort on brew day.

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