Hidden science behind normal and accelerated e-liquid steeping.
We are all aware of the effect of steeping e-liquid can improve its flavour and change its colour.
In this article I am attempting to describe the cause and effect systems involved in e-liquid steeping and accelerated steeping from a scientific viewpoint.
There are two major processes involved in steeping e-Liquid
1. Removal of volatile components by evaporation and degasification
This process would include the removal of alcohol but is not restricted to alcohol, there are other volatile components used in the production of flavour concentrates that generally give off an astringent or chemical odour.
These process requires access to the atmosphere hence the need to remove tops from bottles
1a Evaporation – This is the same process as used in cooking to remove alcohol from wine.
1b Degasification – This is the sameprocess as letting a fizzy drink going flat
Both of these processes are accelerated by heat and increased surface area.
This is a critical first step many e-Liquids are hideous and un-vapeable before this process.
Without acceleration this can take a week or longer due to the viscosity of the liquid.
2. The development of complex flavour molecules.
Over time some e-Liquids especially custard / caramel or desert flavours darken over time
From observation this cannot be oxidation as it occurs uniformly through the liquid and does not require agitation of the liquid to occur.
It also cannot be caramelization as this does not occur below 110°C.
Maillard Reaction - Colour and flavour
What seems to be happening is a Maillard reaction commonly experienced by most people every day. The browning of bread, toast and potato chips these are high temperature examples. Medium temperature examples creating Dulce de leche and condensed milk.
Mallard reactions also occur at lower temperatures and contribute to the aging of wine and Balsamic Vinegar.
Maillard reactions get exponentially slower as they progress
This fits in with our observations of steeping e-Liquid, a golden colour may be observed in a couple of days however the full desired flavor and colour may take 4-6 weeks to develop.
The Maillard reactions will continue to progress over time, hence those almost black bottles of e-Liquid that are found at the back of a draw.
Accelerating the steeping process
Removal of volatile components by evaporation and degasification
a) Taking the top off the bottle.
Evaporation and degasification simply wont happen with the lid on (Think bottle of lemonade)
b) Shaking the bottle (Helps)
c) Stirring (Helps)
d) Whisking (Very effective)
c) Blending to a foam (Super Effective)
d) Ultrasonic degasification (Super Effective)
Video Showing Ultrasonic degasification
http://www.hielscher.com/degassing_01.htm
d) Heating to 40°C-50°C (Accelerates all of the above methods)
Maillard Reaction - Colour and flavour
a) Heating to 40°C-50°C (Maillard reactions go slower at lower temperatures)
b) Ultrasonic treatment (local extremes of temperature and pressure act as a catalyst)
In Practice
The image on the left was taken immediately after mixing the image on the right was taken 5 hours later
60:40 VG PG 18% Nic 15% T-Juice Custard Concentrate
The e-Liquid was very vapeable the next day and is continuing to improve in the bottle.
Method used
a) Mixed liquid by weight directly into the blender cup.
b) Blended to a foam for 15 seconds remove lid
c) Placed into ultrasonic bath pre-heated to 50°C
d) 20 minuet ultrasonic cycle
e) 20 minuet rest
f) repeated (b) to (e) above six times
Then bottled into 50ml bottles
Storing after accelerated steeping.
Storing lid off in warm (room temp) draw or cupboard will allow any new volatiles to escape
This is less important as time passes.
The e-Liquid will continue its Maillard reaction gaining in richness, complexity and darkening
further.
There will be a point where you will not want the process to continue this is of personal preference.
This dictates how much you should make. As the Maillard reaction slows down most e-Liquids have a “Window of Niceness” lasting a couple of months.
The process can be slowed by refrigeration don’t freeze your liquid.
Quality and Issues
There is no quality related advantage accelerating the steeping of e-Liquid.
Heating some flavours may introduce unwanted cooked flavours.
If the acceleration process is overdone the “Window of Niceness” shelf life can be drastically reduced.
Full blown blending is impractical for quantities of less than about 100ml
Good old lid off in a dark place with a bit of a shake now and then will result in a perfectly steeped e-Liquid it is also far more predictable than accelerated steeping. It just takes longer.
As there are so many variables involved, you should always keep notes on how you
have steeped your e-Liquid along with the ingredients. You can then easily replicate your successes.
Joe Dyer
References
Wikipedia entry on Maillard reactions
http://en.wikipedia.org/wiki/Maillard_reaction
Description of low temperature Maillard reactions
http://cooking.stackexchange.com/questions/29926/what-temperature-does-the-maillard-reaction-occur
By
Joe Dyer
We are all aware of the effect of steeping e-liquid can improve its flavour and change its colour.
In this article I am attempting to describe the cause and effect systems involved in e-liquid steeping and accelerated steeping from a scientific viewpoint.
There are two major processes involved in steeping e-Liquid
1. Removal of volatile components by evaporation and degasification
This process would include the removal of alcohol but is not restricted to alcohol, there are other volatile components used in the production of flavour concentrates that generally give off an astringent or chemical odour.
These process requires access to the atmosphere hence the need to remove tops from bottles
1a Evaporation – This is the same process as used in cooking to remove alcohol from wine.
1b Degasification – This is the sameprocess as letting a fizzy drink going flat
Both of these processes are accelerated by heat and increased surface area.
This is a critical first step many e-Liquids are hideous and un-vapeable before this process.
Without acceleration this can take a week or longer due to the viscosity of the liquid.
2. The development of complex flavour molecules.
Over time some e-Liquids especially custard / caramel or desert flavours darken over time
From observation this cannot be oxidation as it occurs uniformly through the liquid and does not require agitation of the liquid to occur.
It also cannot be caramelization as this does not occur below 110°C.
Maillard Reaction - Colour and flavour
What seems to be happening is a Maillard reaction commonly experienced by most people every day. The browning of bread, toast and potato chips these are high temperature examples. Medium temperature examples creating Dulce de leche and condensed milk.
Mallard reactions also occur at lower temperatures and contribute to the aging of wine and Balsamic Vinegar.
Maillard reactions get exponentially slower as they progress
This fits in with our observations of steeping e-Liquid, a golden colour may be observed in a couple of days however the full desired flavor and colour may take 4-6 weeks to develop.
The Maillard reactions will continue to progress over time, hence those almost black bottles of e-Liquid that are found at the back of a draw.
Accelerating the steeping process
Removal of volatile components by evaporation and degasification
a) Taking the top off the bottle.
Evaporation and degasification simply wont happen with the lid on (Think bottle of lemonade)
b) Shaking the bottle (Helps)
c) Stirring (Helps)
d) Whisking (Very effective)
c) Blending to a foam (Super Effective)
d) Ultrasonic degasification (Super Effective)
Video Showing Ultrasonic degasification
http://www.hielscher.com/degassing_01.htm
d) Heating to 40°C-50°C (Accelerates all of the above methods)
Maillard Reaction - Colour and flavour
a) Heating to 40°C-50°C (Maillard reactions go slower at lower temperatures)
b) Ultrasonic treatment (local extremes of temperature and pressure act as a catalyst)
In Practice
The image on the left was taken immediately after mixing the image on the right was taken 5 hours later
60:40 VG PG 18% Nic 15% T-Juice Custard Concentrate
The e-Liquid was very vapeable the next day and is continuing to improve in the bottle.
Method used
a) Mixed liquid by weight directly into the blender cup.
b) Blended to a foam for 15 seconds remove lid
c) Placed into ultrasonic bath pre-heated to 50°C
d) 20 minuet ultrasonic cycle
e) 20 minuet rest
f) repeated (b) to (e) above six times
Then bottled into 50ml bottles
Storing after accelerated steeping.
Storing lid off in warm (room temp) draw or cupboard will allow any new volatiles to escape
This is less important as time passes.
The e-Liquid will continue its Maillard reaction gaining in richness, complexity and darkening
further.
There will be a point where you will not want the process to continue this is of personal preference.
This dictates how much you should make. As the Maillard reaction slows down most e-Liquids have a “Window of Niceness” lasting a couple of months.
The process can be slowed by refrigeration don’t freeze your liquid.
Quality and Issues
There is no quality related advantage accelerating the steeping of e-Liquid.
Heating some flavours may introduce unwanted cooked flavours.
If the acceleration process is overdone the “Window of Niceness” shelf life can be drastically reduced.
Full blown blending is impractical for quantities of less than about 100ml
Good old lid off in a dark place with a bit of a shake now and then will result in a perfectly steeped e-Liquid it is also far more predictable than accelerated steeping. It just takes longer.
As there are so many variables involved, you should always keep notes on how you
have steeped your e-Liquid along with the ingredients. You can then easily replicate your successes.
Joe Dyer
References
Wikipedia entry on Maillard reactions
http://en.wikipedia.org/wiki/Maillard_reaction
Description of low temperature Maillard reactions
http://cooking.stackexchange.com/questions/29926/what-temperature-does-the-maillard-reaction-occur
By
Joe Dyer
