Yadu pub meet 22/9/05, 18h Stokesly High Street, Middlesbrough area.
Participating scientists: Yadunandan Dar (technical consultant) Richard Grove
& Kate Rich (cube cola representatives), Hari Kunzru (driver & facilitator).
The road trip up from London took approximately 5 hours.
- fragrances are alcahols & esthers, fragrances are aldehydes
- molecules that only have hydro & carbon are not soluble in water at all
Water is a continuous phase; the oil particles are a dispersed phase (see serviette)
Adsorb= small molecule->surface
Absorb= small molecules->in like sponge
You're fighting gravity. You use energy to create the interface. If you put different
oils together, the shear (force) breaks up the oils into smaller particles.
Gums are very. very large molecules, made from polymers/natural sugars (polysaccharides).
There's a billion dollar industry, sourcing and selling gums - purely for the cola
sector. Gum Arabica is oldschool, from 19-whatever. It's a hariy, ugly molecule; there's
no real consistency
- it's dependent on the plant. Impurities in the gum solids make them unreliable in the
The gum sits at the interface between the materials - it goes between the particles. Gum
has such a high molecule weight it doessn't like water very much.
Xanthan and Guar gums are not true emulsifiers - they are used as emulsifiers because
they increase the viscosity of the water. The other way to fight gravity is to increase
the viscoisty of the medium, that's where these gums come in. The gum really connects the
particles, it makes a loosley connected network.
Gum affects nouthfeel - a cheaper cola is sticky. Try decreasing the gum from the CNI
recipe proportions, by 50%. You will need more emulsification force (shear) - beat the
hell out of it. Try National Starch & Chemcical Company http://www.nationalstarch.com/
(an ICI subsidiary) for alternate gums.
The shear creates a surface area. Interfaces need energy (what you're fighting is
gravity); multiple phases need a lot of energy. You want to make the particles as small
as possible. The more shear, the smaller the particle, the more surface area is in the
interface. 1-5 microns is about the right border, if you're above that, it's not going
to work. 300-500 nanometers is good. There's 1000 nanometers in a micron.
- accelarated testing
If you want to test your emulsion without laboratory equipment, you elevate the
temperature. Put it in the oven - 50 degrees Centigrade for a week. Or 70,80 degrees for
one hour. Put the whole syrup in, not just the pre-emulsion. Seal the bottle or you'll
lose water. It's going to separate, but you'll get to see which emulsion is going to work
Alcahol likes water (hydrofelicitous), it is instantly soluble, like a gin & tonic. In
the pre-emulsion, alcahol can absorb some of the water and increase the molecule density.
The energy of the interface goes down a bit: it helps stabilise the interface. Glycerin
is a higher alcahol, ethanol is a lower alcahol. The reason to use alcahol in the
pre-emulsion: if you slightly increase the water-solubility of the particles you decrease
the density difference between them. You can't remove the high hydrocarbons, but alcahol
can increase the hydrofelicity, help it like water more.
The Bosch cordless is probably doing around 2500 revs - not so fast. A balloon whisk is
not the best way of doing this. Try a wand blender (bamix) - 5000-15000 revs is good -
but actualy it's not about RPM speed, shear is more important. The blade's proximity to
the vessel. Get a bamix with its own goblet. You can't really overshear, at this level.
Get a professional kitchen blender - a Bosch is good, around 60-70 GBP or a Kitchenaid
which is twice as much.
Wherever you go in the world, you will always find 1 Chinese & 1 Indian guy. In the same
way, there's water in flavour oils - very little, 50 ppm (parts per million), but it is
-toxicity of neat essential oils: orange oil is the most toxic
- Do a 250ml batch, for the pre-emulsion (7x formula). Scaling up further would need
A lot of the hardware's proprietary.
- Use alcahol in the pre-emulsion: 2% (by weight) of the flavour oils.
Glycerin, ethanol of good vodka. Aboslut or Everclear (Wisconsin) which is 180 proof /
90%. You can also use alcahol in the emulsion (syrup phase) to draw out some of the more
hydrophobic particles in this case the alcahol gets removed - but this is a later stage.
- Water: go for something with less calcium but also less magnesium
(low divalent metal ions).
- Phosphoric acid is slightly preferable to citric. Coke uses phosphoric.
- The accelarated salad dressing test. Oil and vinegar with variable hardware / gum
levels / mix durations, oven tested.
- Test the emulsion with 3 different graphs, plot shear vs gum loading, 3 different
settings for each & screen it in the oven to see which emulsifies longest. What do
accelarating test separations represent in non-oven time? People have been tring to
answer this question for hundreds of years.
- taste test: not bad. more pepsi than coke.
too much cinnamon in first taste (cheap-cola); too much nutmeg in aftertaste. On the
upper palate you get a texture - it might be gum.