A small glass of tea made with fluid gels. An interesting effect of gels is that when you shear them into small pieces they want to hold back into a gel structure but at the same time they take on a delicate fluid like state. This recipe takes advantage of this effect by pushing this effect to its limit: when it is at rest the two gels are independent and held up against each other with no barrier in the glass. They are strong enough that lifting the glass will not ruin the effect. However, tilting the glass will and they will flow like a liquid.
Additionally this is a vegan recipe as the gel is based on gellan, a gelling agent derived from sphingomonas elodea, a bacteria derived from lily pond water.
One side dyed in the picture to show the effect but here is another picture of another preparation:
This is 2 gels in the same glass held against each other. Think of the 
The layers in that stay separated. This follows the same concept. But in the tea glass instead of using colors to differentiate the layers the layers are differentiated by temperature.
This results in a small glass of tea where you have both hot tea and iced tea. When you drink it both sensations hit your tongue and mouth at the same time. It’s quite confusing and very interesting
This recipe was created by chris young, who was working for Heston blumenthal at the fat duck.
It is labor intensive and takes some effort but if you want to surprise your guests this 100% will do it.
Hot and iced tea:
Tea infusion:
1.8kg low calcium water: the water should have between 100-400 ppm calcium. Too much and the gel will be lumpy. Too little and it will not set. I use Evian, which is about 80ppm, and add 36mg calcium chloride. You will use calcium chloride later so this isn’t a waste. You don’t need to measure super precisely because this just brings you up to the lower limit of 100ppm for the 1.8kg (however you may want to make much less)
40g tea
Cold infuse the tea in the water - this part is easy. Put the tea leaves in the water and wait. Infuse for at least one hour but not too long. Taste and make sure bitter notes aren’t infusing. 1 hour is often enough.
Strain the mixture. - strain it through a fine sieve lined with a coffee filter. You want it super clear.
Now comes the more difficult part
Hot tea
Part A:
860g tea infusion
80g ultrafine sugar (caster, superfine, bakers sugar)
0.6g gellan F
0.6g sodium citrate
Part b:
0.25g calcium chloride
1g malic acid
5g tea infusion
Prepare ice bath
Bring tea infusion to a simmer. Dry blend part A. Whisk in until dissolved. Mix part B. Once part A is simmering remove from heat, add part b, whisk in, place over ice bath, continue whisking as long as you can, ideally until cool. If you have an automated stirrer that’s the best.
Refrigerate 24 hours then pass through a very fine sieve (I use a 250um lab sieve) then bottle in a squirt bottle (like a condiment bottle).
Cold tea:
Part A:
860g tea infusion
80g ultrafine sugar (caster, superfine, bakers sugar)
0.6g gellan F
0.6g sodium citrate
Part b:
0.25g calcium chloride
3.5g malic acid
5g tea infusion
Prepare ice bath
Do the same exact preparation.
To serve:
Prepare the hot tea: you can either put it in a water bath if you have a sous vide at 162F, or you can microwave it until it’s hot enough, or you can put it in simmering water, etc. the first is the easiest but obviously you need the equipment. The microwave works in a pinch, just shake it up, taste test, go in small increments to make sure you’re not serving lava.
For the glass you need a divider. I use aluminum foil formed to the glass. This doesn’t give the cleanest line as shown in the dyed preparation. In the hot/cold one it doesn’t really matter. In chris youngs video where he does this with coffee he does reveal that he simply made a divider with more gellan to fit the glass. Simple. He doesn’t reveal the recipe though, nor the adaptations to make it work with coffee (there’s also a mulled wine version they served at least once at the fat duck). Youtubers always assume their audience is dumb or maybe he needs hestons permission to release the recipe, I dunno.
Once you have the hot heated up and the divider you’re ready to go. There’s a technique to this but it’s not terribly hard. Basically pour each side evenly then pull the divider out smoothly and as straight up as possible. Try to make the divider as thin as possible. From here serve as quickly as possible because the hot and cold sides will cool and heat each other. Even a few minutes will have you just serving a weird thick glass of tea.
But if you get it right you serve a glass of tea that look almost entirely normal. There is a slight difference in each side, one is slightly darker, but it is very subtle. I specifically use a glass with a handle because if you grab the glass it totally gives it away.
