Last night was the inaugural London Gastronomy Seminar, focussing on flavour extraction. The speakers were Hervé This, one of the first to investigate molecular gastronomy, and John Forbes of R C Treatt, a major manufacturer of essential oils and natural flavours. Both were great presentations, in totally different styles.
Unfortunately Tony Conigliaro, owner of 69 Colebrooke Row, had broken his foot and couldn’t speak – but he did send along a bottle of amazing rotovapped horseradish vodka, which was incredibly smooth, with the flavour of horseradish, but not the bite.
Pictures of the handout are here, and very rough notes follow:
Hervé This
Gastronomy has nothing to do with cooking. “Gastronomy is the maturer knowledge—the rationale of everything which concerns man as regards his food.” – Brillat-Savarin
There is no ‘science of the oven’. Science is not technology – science is not applied! Chefs don’t make molecular gastronomy, they may make molecular cooking.
Scientific method – look at a phenomenon, make measurements, synthesize into laws, explain by theory, make predictions and an experiment to test. Refute, or not, and repeat.
Original mission in 1988 of molecular gastronomy: Investigate recipes, explore old wives’ tales, invent new dishes, introduce new tools and ingredients, use cooking to show that science is wonderful.
But, invention is not science! This is not a list of scientific undertaking.
Look at a cookbook… a recipe has 3 parts: definition (ingredients, preparation), useless/literary/readable words, precisions (how much, exact instructions).
2005 mission of research: Explore definitions and precisions. Explore the art component of cooking. Explore the love component of cooking.
“New” tools: from any chemistry lab – vacuum syphons, rotary evaporator, distillation equipment.
“New” ingredients – alginates etc.
“New” processes – ice cream with liquid nitrogen. Actually invented in 1907 in London!
So these things are not really new – just new in cooking.
Work closely with Pierre Gagnaire – has one new idea a month, that Pierre turns into a recipe.
Monthly free, open discussions plus workshops, seminars in Paris. All reports on the Internet – in French (e.g.).
Note-by-note cooking: previously recipes asked for a carrot, an egg etc. What about using compounds as the ingredients, rather than food that is mixtures of compounds already?
Take some water, add sucrose, ethanol, grape flavour, glucose, and a little oil. You have wine!
Use compounds to create odour, taste, colour, texture… 1st note-by-note recipe cooked by PG – it was fantastic! Impossible to describe the taste, like it would be impossible to describe the smell of a rose without prior knowledge.
(unfortunately Hervé This had to run for a plane or something, so the presentation was rather quick and he couldn’t go into details)
John Forbes
Treatt Plc – produces flavour ingredients for the flavour industry, mainly using natural ingredients.
Started in 1886, producing ambergris and other essential oils for the perfume industry. In 1930, worked with Rose Company to create lime oil from waste lime peels (from making the cordial).
Essential oils are hydrophobic. Sources are leaf, seed, flowers, bard, wood, roots/rhizomes, fruits, peel, exodate. Not extracting the fatty oils, used for cooking. They travel the world to source the raw ingredients (it was noted later that one problem is keeping the flavour stable as raw product changes and different species are used).
Steam distillation – basic process, the traditional way. E.g. used to extract peppermint oils.
Citrus – FMC machines extract oil at same time as the citrus is being juiced. Water is washed over the skin, and then centrifuged off.
100Kg oranges produces 55Kg of orange juice. Either sold as fresh or concentrated down to 10Kg of 65° BRIX FCOJ (frozen concentrate orange juice) – the same sugar level as jam. 0.03Kg of cold pressed oil.
[also explained about the FCOJ industry – I was reminded of Trading Places – including pictures of the European Juice Terminal in Rotterdam]
Brown oil extractor – a different method, uses pins to prick the citrus skin cells.
Orange oil is the 2nd biggest essential oil – first is turpentine.
Green oranges can be ripe – need cold to break down the chlorophyll.
d-limonene is the major citrus peel oil. l-limonene (the other handed variant) has a metallic smell, contained in spearmint.
d-limonene oxidizes into l-carvone – spearmint smell. d-carvone has a dill smell.
[explains gas chromatography]
different peaks, not just one oil.
range of related molecules – octanal, decanal…
sinesal – also projuced when fats degrade – 150 tons of OJ will produce 0.5kg of sinesal.
Orange juice oil – valenciene – woody smell.
Ethyl butyrate – over ripe fruit smell – in fruit sweets, juicy fruit.
Cis-3-hexenal – cut grass.
Also produced during concentration is an orange waterphase – water-soluble volatile compounds. This is re-added to the concentrate, in different ratios, however the company want to orange juice to taste.
Limonene burn if too much is added – 350ppm of oil.
Grapefruit oil – nookatone – dry,powdery grapefruit small (discovered in the 1960s).
Lemon oil – citral (two compounds – neral and geranial), beta-bisabolene. Citral in things like lemonade, other lemon flavour products.
Key lime – beta-bisabolene + farnesene.
Citral isn’t very stable – half-life of 6 days in pH 3 (such as a fizzy drink). There are clever ways to get round this, but sometimes you may taste lemonade that tastes odd.
olfactometry – smelling the broken apart gas from gas chromatography. Interesting, but very hard to do. Sometimes compound peaks correspond with a reduction in smell – there is competition between compounds, it isn’t just additive.
260 volatile compounds in oil of grapefruit. 48 are odour-active, but only 17 are measurable by gas-chromatography. Often, the oils in largest quantity don’t contribute much to the actual flavour, such as limonene. Some of the most important can be a few ppm (hard to detect and hard to produce).
Now producing water distillates of flavours that can’t be captured by traditional means, where an oil layer doesn’t occur. Cucumber, roast peppers… tea, sugars, honey, malt.
[During the presentation, we got to smell several types of orange and orange juice oil, plus some of the individual chemicals, and some water distillates. This was excellent, and they were incredibly strong – they lingered in your mind, and made it very hard to think about what I wanted for dinner.]
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