WELCOME TO THE GTT-CAFÉ
At the 2025 Users' Meeting, the GTT-Café will open its doors — or rather, its portafilter — for the first time. Stephan Petersen, one of the managing directors of GTT-Technologies, will personally serve specialty drinks with scientific depth. For a refined taste, and even better conversations.
And while 'GTT' usually stands for 'Gesellschaft für Technische Thermochemie und -physik', in this café it simply means: Grind. Temp. Taste.
YOUR DAILY PHASE TRANSITION: FROM TIRED TO INSPIRED
THERMAL EXCITATIONS
ESPRESSO
Compact, pressurized, and pure: A near-adiabatic, high-pressure transformation representing the thermodynamic limit of liquid-phase flavor release.
Stream #1 | Species: Espresso beans (reg. / decaf) | Quantity: 3 g (single) / 6 g (double) | T: 23 °C | P: 1.0 bar
Stream #2 | Species: H₂O | Quantity: 25 g (single) / 50 g (double) | T: 93 °C | P: 9.0 bar
Final conditions | Quantity: 16 g (single) /32 g (double) | T: 68 °C | P: 1.0 bar | maximum intensity
AMERICANO / LONG BLACK
An isothermal expansion of espresso into a diluted aqueous phase. Americano adds water to espresso; Long Black reverses the order.
Stream #1 | Species: Espresso beans (reg. / decaf) | Quantity: 3 g (single) / 6 g (double) | T: 23 °C | P: 1.0 bar
Stream #2 | Species: H₂O | Quantity: 25 g (single) / 50 g (double) | T: 93 °C | P: 9.0 bar
Stream #3 | Species: H₂O | Quantity: 85 g | T: 75 °C | P: 1.0 bar
Final conditions | 80 °C | 1.0 bar | supersaturated diffuse flavor
CAPPUCCINO
Meta-stable foam structure: Espresso entrained in aerated milk microbubbles, governed by surface tension and phase instability.
Stream #1 | Species: Espresso beans (reg. / decaf) | Quantity: 3 g (single) / 6 g (double) | T: 23 °C | P: 1.0 bar
Stream #2 | Species: H₂O | Quantity: 25 g (single) / 50 g (double) | T: 93 °C | P: 9.0 bar
Stream #3 | Species: Milk (reg. / lactose free / oat / soy) | Quantity: 170 ml | T: 60–65 °C | P: 1.0 bar
Final conditions | 65 °C | 1.0 bar | semi-stable, meta-aerated
LATTE
Two-phase dispersion system of espresso and steamed milk, stabilized at elevated enthalpy with smooth textural coherence.
Stream #1 | Species: Espresso beans (reg. / decaf) | Quantity: 3 g (single) / 6 g (double) | T: 23 °C | P: 1.0 bar
Stream #2 | Species: H₂O | Quantity: 25 g (single) / 50 g (double) | T: 93 °C | P: 9.0 bar
Stream #3 | Species: Milk (reg. / lactose free / oat / soy) | Quantity: 170 ml | T: 60–65 °C | P: 1.0 bar
Final conditions | 60 °C | 1.0 bar | rich texture, creamy diffusion
VARIOUS TEAS
From green to black, from oxidized to roasted: Thermodynamically diverse plant infusions, steeped across enthalpic gradients to extract polyphenols, aromatics, and tradition.
Stream #1 | Species: Tea leaves (various) | Quantity: 1 Tea bag | T: 22 °C | P: 1.0 bar
Stream #2 | Species: H₂O | Quantity: 190 ml| T: 95–100 °C | P: 1.0 bar
Final conditions | 55-70 °C | 1.0 bar | tannin-guided aromatic profile
KINETIC COOLDOWNS
ICED LATTE
A quenched two-phase system, where espresso equilibrates into chilled milk to yield diffusion with preserved aromatic integrity.
Stream #1 | Species: Espresso beans (reg. / decaf) | Quantity: 3 g (single) / 6 g (double) | T: 23 °C | P: 1.0 bar
Stream #2 | Species: H₂O | Quantity: 25 g (single) / 50 g (double) | T: 93 °C | P: 9.0 bar
Stream #3 | Species: Milk (reg. / lactose free / oat / soy) (cold) | Quantity: 50 g | T: 4 °C | P: 1.0 bar
Stream #4 | Species: H₂O | Quantity: 50 g | T: 0 °C | P: 1.0 bar
Final conditions | 7 °C | 1.0 bar | low-enthalpy delight
ICED AMERICANO / LONG BLACK
A rapid thermal drop across espresso and cold water, driven by entropic dilution and preserved solute saturation.
Stream #1 | Species: Espresso beans (reg. / decaf) | Quantity: 1.00 mol (single) / 2.00 mol (double) | T: 23 °C | P: 1.0 bar
Stream #2 | Species: H₂O | Quantity: 15.00 mol (single) / 30.00 mol (double) | T: 93 °C | P: 9.0 bar
Stream #3 | Species: H₂O | Quantity: 85.00 mol | T: 6 °C | P: 1.0 bar
Stream #4 | Species: H₂O | Quantity: 10.00 mol | T: 0 °C | P: 1.0 bar
Final conditions | 7 °C | 1.0 bar | crisp dilution, layered extraction
COLD BREW
An ambient-time extraction driven by slow kinetics, optimized for polyphenol richness and reduced acidity over 16–20 hours.
Stream #1 | Species: Coffee (Rungeto / Yirgacheffe / Nansebo) | Quantity: 100 g | T: 22 °C | P: 1.0 bar
Stream #2 | Species: H₂O | Quantity: 100 ml | T: 4 °C | P: 1.0 bar
Stream #3 | Species: H₂O | Quantity: 10 g | T: 0 °C | P: 1.0 bar
Final conditions after 16 h of full immersion | 10 °C | 1.0 bar | polyphenol-rich and low-acidic spectrum
COLD BREW HŌJICHA
A roasted-tea cold infusion system, favoring aromatic integrity and delicate volatiles through low-energy extraction pathways.
Stream #1 | Species: Cold brew tea (Hojicha) | Quantity: 10 g | T: 22 °C | P: 1.0 bar
Stream #2 | Species: H₂O | Quantity: 1000 ml | T: 68 °C | P: 1.0 bar
Final conditions after 6 h of full immersion| 10 °C | 1.0 bar | gently preserved aroma spectrum
ROSEMARY ESPRESSO SPRITZ
A volatile, gas–liquid equilibrium system: Espresso meets homemade rosemary syrup and sparkling water, creating a botanical effervescence with layered aromatic lift.
Stream #1 | Species: Espresso beans (reg. / decaf) | Quantity: 3 g (single) / 6 g (double) | T: 23 °C | P: 1.0 bar
Stream #2 | Species: H₂O | Quantity: 25 g (single) / 50 g (double) | T: 93 °C | P: 9.0 bar
Stream #3 | Species: Soda water | Quantity: 50 ml | T: 6 °C | P: 3.0 bar (carbonated)
Stream #4 | Species: Rosemary syrup (homemade) | Quantity: 15.00 mol | T: 6 °C | P: 1.0 bar
Stream #5 | Species: H₂O | Quantity: 50 g | T: 0 °C | P: 1.0 bar
Final conditions | 6 °C | 1.0 bar | sparkling, herbaceous phase transition
THE ESPRESSO BEANS
CAFFÈ BORBONE – CREMA SUPERIORE
A pressure-optimized Neapolitan blend: rich, smooth, and creamy. Crafted for full-bodied extraction with balanced sweetness and enduring elegance.
Roaster: Caffè Borbone, Naples, Italy | Content: 80 % Arabica, 20 % Robusta | Intensity: 7/10 | Awarded: Superior Taste Award, International Taste Institute, Brussels
GOLDEN BASIL DECAFFEINATO ESPRESSO
A well-balanced decaf blend, gently aromatic and softly structured, uniting sweet Central American Arabicas with the chocolaty depth of Asian Robustas.
Roaster: Dacatè Srl, Pomezia, Rome | Content: 70 % Arabica, 30 % Robusta | Caffeine content: < 0.10 % | Decaffeination: Swiss Water Method
THE COLD-BREWED ORIGINS
RUNGETO
A vibrant Kenyan profile grown grown at 1750 meters on volcanic soil: Bright, fresh, and tangy, with crisp acidity and layered citrus clarity.
Roaster: Rungeto Co-operative Society, Kirinyaga, Kenya | Content: 100% Arabica (SL-28, SL-34, Ruiru 11) | Processing: Washed | Roast: Very light | Strength: 3/5 | Acidity: 4/5
YIRGACHEFFE
An elegant heirloom expression: Complex, floral, and fruit-driven, with signature berry notes and refined spice from the Ethiopian highlands.
Roaster: Smallholders, Konga, Yirgacheffe, Ethiopia | Content: 100% Arabica (Local landraces) | Processing: Washed | Roast: Light–medium | Strength: 3/5 | Acidity: 4/5 | Certified Organic
NANSEBO
A fruit-forward natural-process coffee with notes of ripe berries and floral sweetness: Vibrant, juicy, and as refreshing as a chilled summer fruit snack.
Roaster: Nansebo Washing Station, Sidamo Zone, Ethiopia | Content: 100% Arabica (Local Ethiopian Variety) | Processing: Natural | Roast: Light | Strength: 3/5 | Acidity: 4/5
HŌJICHA ほうじ茶, 焙じ茶
A roasted green tea with low caffeine and high character: Slow-fired over charcoal at 150 °C, yielding golden hues, nutty aromas, and a smooth, mellow profile unlike any steamed green tea.
Roaster: Japan (various producers) | Content: Green tea (Camellia sinensis) | Processing: Roasted, whole leaf | Caffeine: Low | Roast: Medium–dark
