Taking Density With Hydrometers

Taking Density With Hydrometers

Density is measured in sake via hydrometers to determine fermentation progress and sweetness/dryness. Baume and SMV are the density scales typically used in sake brewing. Baume/SMV has an equivalent to Specific Gravity, Plato, and Brix but other scales can be more difficult to read with precision.

There are two types of Baume scales, a heavy scale for liquids denser than water and a light scale for liquids less dense then water. The Baume Light scale is not typically referenced in sake brewing, instead a specialized hydrometer called the Sake Meter Value (SMV) is used to read density when sake transitions from more to less dense than water.

Specific Gravity 1.0149 1.0079 1.00087 1.0000 0.9940 0.9872
Baume Heavy 2 1 0
Baume Light 8 9 10 * 11 12
Sake Meter Value -20 -10 0 1.26 10 20

Text book of Sake Brewing P118: Table 5-4 Relationship between Specific Gravity, Sake Meter Value, and Baume Degree

The range of Baume heavy hydrometers is between 20 and 0. An SMV hydrometer is equivalent to Baume between 3 to 0 but also goes lower. These numbers are equivalent to -30 and 0 respectively and then lower down to +20. For example if you have a baume heavy reading of 1.2 you will have an equivalent SMV reading of -12.

Needs:

Method:

  1. Place sample in graduated cylinder
  2. Place appropriate hydrometer into sample
  3. Read and record your result


ABV via Ebulliometry

ABV via Ebulliometry

This method of finding ABV uses a piece of equipment called an ebulliometer. Water has a boiling point but alcohol has a lower boiling point. By finding the boiling point of a sake sample and comparing it to the boiling point of water you can figure out how much alcohol is in your sake.

Water will boil at different temperatures depending on atmospheric pressure. It is essential to take a baseline temperature of distilled water before testing a sake sample.

Sake has a high content of alcohol and this can affect the reading of the ebulliometer. To account for this a simple 1:1 dilution can be done and the results adjusted by doubling it.

Glucose content can also affect the reading of the ebulliometer. A correction can be applied by finding the Baume (see below).

Needs:

Method:

  1. Baseline Test with Distilled Water
    1. Flush the Ebulliometer chamber with distilled water
    2. Measure out ~100ml of distilled water and add to the chamber
    3. Turn on flow of cooling water
    4. Turn on Ebulliometer and allow to come to a boil
    5. Record the baseline temperature once the temperature has stabilized
  2. Sake sample test
    1. Flush the Ebulliometer chamber with distilled water
    2. Measure out 50ml of sake sample and mix with 50ml of distilled water
    3. Flush Ebulliometer chamber with sake dilution
    4. Measure another 50ml of sake sample and mix with 50ml of distilled water
    5. Fill Ebulliometer chamber with sake dilution
    6. Turn on flow of cooling water
    7. Turn on Ebulliometer and allow to come to a boil
    8. Record the sake sample temperature once the temperature has stabilized
  3. Subtract the two numbers and compare the result on the chart to find the ABV, then double the ABV percentage to account for your dilution

Correction for glucose:

  1. Calculate the Alcohol by following the above procedure.
  2. Using a Baume hydrometer determine the Baume reading ofย  your sake sample. The Baume must be >0.5 for the conversion to be applicable.
  3. Adjust the result by applying the following method:
    • Final Alcohol = Apparent Alcohol x [1-(Baume x 0.015)]


Sampling of Mash

Sampling of Mash

Getting a clear filtered sample of sake is essential to getting proper results for your laboratory analysis. Most samples are taken in the morning with analysis being done in the afternoon to allow time for the sample to filter.

Needs:

Method:

  1. Fold Qualitative paper to fit nicely inside of funnel
  2. Place funnel on top beaker
  3. Pour sample into the filter
  4. Cover and and allow to filter at room temperature for several hours


Total Acidity By Titration

Total Acidity By Titration

Acidity is important to monitor to ensure fermentation is progressing and no outside organisms have taken a hold.

Needs:

Method:

  1. Take a 10ml sample of your sake at 15C and place in beaker
  2. Add 4 drops of the phenolphthalein indicator to the beaker
  3. Fill your titration pipette to 10ml of Hydrochloric Acid.
  4. Place the indicator beaker underneath the pipette and slowly drip the hydrochloric acid into your sample solution, swirling or using a stir plate. A bright pink drip will appear in the solution and will disappear as you swirl the mixture. Look for the clear solution to turn pink and remains pink for more than 30 seconds.
  5. Take reading of how much hydrochloric acid was added
  6. Multiple that number by .75 to get your Total Acidity or Sando.