In this post you will learn how to use tools to measure the amount of Sugar in your juice. This will be needed to know when your cider is done fermenting and to calibrate the approximate amount of alcohol a particular juice blend will create.
Tools you may need to complete this task:
- A Glass Hydrometer Test Jar or Plastic Hydrometer Test Jar
- Wine Thief
- Hydrometer – Triple Scale
- Triple Scale Hydrometer and Test Jar Combo (Kit)
Hydrometers work by measuring the density of the liquid (apple juice) against the density of a neutral liquid (water). This gives us the difference in liquid densities, basically it is telling us how much sugar and other particles are suspended in our apple juice.
Most Hydrometers have three readings:
- Specific gravity – Measures the relative density of liquids.
- Approximate alcohol by volume – This will give us a guesstimate of the final alcohol content
- Brix – Measures the sugar content based on the beverage temperature.
To measure the sugar content using the hydrometer first thing is to pour juice into the Glass Hydrometer Test Jar (I like the glass ones but you can get a nearly indestructible plastic one Plastic Hydrometer Test Jar ) until the hydrometer is no longer resting on the bottom. Actually you want it about an inch or two from the bottom. If you have enough juice just fill the cylinder all the way to the top and lower the meter in. The juice will run over the sides but that is ok. If you are taking a reading from an already fermenting juice , please, please, please, use a Wine Thief or other “sanitary method” of removing some of the liquid from your fermentor, as you do not want to ruin a whole batch with one careless mistake. Make sure that there are no bubbles attached to the glass body of the hydrometer as they can lift it up and out of the juice, messing with your reading. A good idea is to spin it in the liquid a few times causing the bubble to release from the sides of the hydrometer. This procedure works because the solids (mainly sugars) make the liquid more dense, lifting the hydrometer higher up in the liquid, and of course the more sugar, the higher the reading.
Once the hydrometer is no longer bobbing up and down or spinning you want to take your measurement. The measurement is taken at the lowest point of the liquid (the meniscus) and as you can see in the image below, the liquid creates a dip between the cylinder walls and the hydrometer.
Make notes of the readings you get for S.G. and for *Estimated* alcohol levels. You need to use the adjustment for the temperature of the liquid if different from the calibrated value. See your owner’s guide that came with your hydrometer,. If you don’t have one use the one below.
**NOTE** All Hydrometers are calibrated for different temperatures. Check your hydrometer, if it is not calibrated for 68 degrees F or 20 degrees C, this chart will NOT work for you.
2. Refractometer – Beer brewers use this method frequently, it is simply the amount of light that gets refracted off the sugars in the juice. You use a refractometer (you can act like a pirate if you want, “Argh matey”) that is calibrated to show the brix level (“sugar content of an aqueous solution” Wikipedia) of the juice by reading the reflective index of the sugars. A little juice is placed on the (Clean and Dry) surface of the refractometer. Once it is all closed up, you simply point it at direct light. You will also need to know the room temperature to calibrate your reading. Most home cider makers use the hydrometer method. However, the refractory method is nerdy cool.