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