Ethanol Freeze Protected Water Solutions

Freezing and flash points of ethanol based water solutions or brines

Ethanol based Water Solutions Freezing Point

Freezing Point
Ethanol Concentration
(% by volume)
Temperature (oF) 32 25 15 5 -10 -25 -35 -55 -75 -110 -175
(oC) 0 -4 -9 -15 -23 -32 -37 -48 -59 -73 -115

Flash Points of Ethanol based Water Solutions

The flash point of a chemical is the lowest temperature where it will evaporate enough fluid to form a combustible concentration of gas. The flash point is an indication of how easy a chemical may burn.

Flash Point
Ethanol Concentration
(% by weight)
Temperature (oF) 144 120 97 84 79 75 72 70 68 63 63
(oC) 62 49 36 29 26 24 22 21 20 17 17


  • HIGH flammability if pure

Alternatives to Ethanol based Water Solutions

Example - Ethanol Concentration at Freezing Point at -20oC

The ethanol concentration with freezing point at -20oC can be calculated by interpolating the concentration between freezing point -15oC and -23oC in the table above.

(((40%) - (30%)) / ((-23oC) - (-15oC))) ((-15oC) - (-20oC)) + (30%) = 37.3 %

This calculation is simplified by assuming that the concentration vs. freezing point follows a straight line. This not necessary correct.

If a 90% ethanol-water solution shall be mixed with clean water to achieve a freezing point of -20oC (ethanol concentration 37.3% (0.373)) - the amount of added water can be calculated with volume balance - the amount of ethanol before mix is the same as after the mix:

cs Vs = cm (Vs + Vw)                                                        (1)


cs = concentration in ethanol - water solution 

Vs = volume of the ethanol - water solution (liter, gallon)

cs = concentration in mix

Vm = volume of mix (liter, gallon)

Vw = volume of the added clean water (liter, gallon)

Rearranging the equation to express the volume of water added to the mixture

Vw = (cs - cm) Vs / cm                                                     (1b)

Substituting with values

Vw = (0.9 - 0.373) Vs / 0.373

     = 1.41 Vs

- for every liter 90% ethanol-water solution 1.41 liter of clean water must be mixed in to achieve an ethanol concentration of 37.3% and freezing point -20oC.

Related Topics

  • Material Properties - Material properties for gases, fluids and solids - densities, specific heats, viscosities and more
  • Melting point - freezing point - Documents giving melting or freezing point of elements and different kind of chemical species at varying conditions

Related Documents

Tag Search

  • en: ethanol water freezing flash point
  • es: etanol punto de inflamación de congelación del agua
  • de: Ethanol-Wasser-Frostflammpunkt

Search the Engineering ToolBox

- "Search is the most efficient way to navigate the Engineering ToolBox!"

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your SketchUp model with the Engineering ToolBox - SketchUp Extension/Plugin - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Translate the Engineering ToolBox!
About the Engineering ToolBox!