Hidden science behind normal and accelerated e-Liquid steeping

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Hidden science behind normal and accelerated e-Liquid steeping
E-liquids General

By

Joe Dyer 11/06/2015

Hidden science behind normal and accelerated e-Liquid steeping.

We are all aware that steeping an e-Liquid can improve its flavour and change its colour.
Here I am attempting to describe the cause and effect systems involved in 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 same process as letting a fizzy drink go 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 flavour 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
d2968993ee1838978df9df5537c934ee3ae4ee44.jpg


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 minute ultrasonic cycle

e) 20 minute 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 an unwanted cooked flavour

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.

References

Wikipedia entry on Maillard reactions

en.wikipedia.org
220px-Brioche.jpg

Maillard reaction
The Maillard reaction (/maɪˈjɑr/ my-YAR; French pronunciation: [majaʁ]) is a chemical reaction between amino acids and reducing sugars that gives browned foods their desirable flavor. Seared steaks, pan-fried dumplings, breads, and many other foods make use of the effect. It is named after French chemist Louis-Camille Maillard, who first described it in 1912 while attempting to reproduce biological protein synthesis. The reaction is a form of nonenzymatic browning which typically proceeds rapidl...

Description of low temperature Maillard reactions

cooking.stackexchange.com

What temperature does the Maillard reaction occur?
asked by Athanasius on 05:44PM - 09 Jan 13
temperature, maillard
By

Joe Dyer 11/06/2015

source: http://forum.e-liquid-recipes.com/t...ormal-and-accelerated-e-liquid-steeping/21024
 
Last edited:
Brilliant article.
Something that we all speak about all the time in our little circles
 
As someone who's mad about the science of cooking, seeing that they speak about the maillard reaction immediately shouts BS to me.

"a chemical reaction between amino acids and reducing sugars"

Where are these amino acids? I highly, HIGHLY doubt that there are any. However the oxidation of nicotine DOES cause a darkening. Anyone can test this. Mix a 0mg and a 18mg juice and pop em both in the sun for a few days. The 0mg won't change much, the 18mg will darken severely.

Although this is accurate in terms of effective steeping and degassing (which I have experienced first hand in 0mg juices - I'm looking at you fruit punches), I'm still unsure whether oxidised nic is either good or bad as well as whether it has an impact on the amount of nicotine absorbed. Nicotine has a shelf life, these methods are shortening that drastically. Some nicotine becomes harsher when oxidesed, supposedly extremely high purities become smoother - I've can only speak to it being harsher.

This is a very curious topic filled with psuedoscience, take all claims with a cup of salt until someone can give us some numbers from a lab.
 
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