Light Bite
Aero, a famous brand of chocolate bar, contains bubbles in a chocolate matrix. The bubbles are evenly sized and distributed throughout the whole bar. How do the manufacturers produce this effect? Why don鈥檛 the bubbles rise to the surface as the chocolate solidifies?
鈥� The way in which the unique Aero bubbles are added is a top-secret process closely guarded by Nestl茅 Rowntree. We can tell you, however, that there are approximately 2200 bubbles in one Aero chunky bar!
Marie Fagan
Advertisement
Press and PR Officer, Nestl茅 UK
鈥� Secret details may be absent but the broad answer is in Rowntree鈥檚 British patent GB 459583 from 1935.
The chocolate is heated until it is in a fluid or semi-fluid state, then it is aerated, for example using a whisk, to produce many tiny air bubbles distributed throughout the chocolate. This is poured into moulds and the air pressure greatly reduced as the chocolate is cooled. The reduced air pressure causes the tiny bubbles to grow and gives the finished chocolate its frozen bubbles appearance (see photo). The solid chocolate coating on the surrounding surfaces of the bar is placed into the mould before the aerated fluid chocolate is poured in.
The patent gives no clues on how the bubbles are prevented from rising to the surface during manufacture, but this may be due to the high viscosity of the semi-fluid chocolate and the rapid rate of cooling.
Patents provide a great source of technical information. It has been suggested that 80 per cent of technical disclosures appear in patents and nowhere else. You can view and print GB 459583 using the free espcenet service on the Patent Office website, The service provides an interface to British and European patent offices for you to search their databases.
Melvyn Rees
Marketing and Information Division, The Patent Office, London, UK
鈥� It鈥檚 not the chocolate answer that your reader was looking for, but I was once told that a soap manufacturer used the same process to make floating soap. The experiments were a technical success, inasmuch as the soap floated, but the product was not commercially viable because it dissolved too quickly.
Mike Dignen
Norwich, Norfolk, UK
鈥� David Bailey of Brookes Batchellor patent attorneys in Tunbridge Wells, Kent, UK, also picked up on another patent, GB 459582 and so did Armen Khachikian of the British Library鈥檚 patents information section. This was filed by Rowntree on the same day as the one mentioned above and contains the 鈥淎ero鈥� concept. The chocolate makers clearly knew what they were about. Khachikian points out that eight days before lodging the patent, the Aero name was trademarked. Although British patents expire 20 years after they are filed, the trademark on the name Aero is still in force.
Thanks also to Tom Jackson of Wigton, Cumbria, UK, for ferreting out US patent 4272558 and British patent GB 480951 from 1938 on 鈥淚mprovements in confections for eating or for making into beverages鈥� filed by Sydney Phillips and Arthur Whittaker. This patent contains information on making bubbles in molten chocolate with pressurised gas and then discharging the gas through a nozzle. It states: 鈥淭he releasing of the chocolate into a region at atmospheric pressure causes the gas to escape from or expand within the chocolate, giving the chocolate a porous, cellular, honeycomb-like open structure.鈥� 鈥� Ed
This week鈥檚 questions
Call me for dinner
I placed my mobile phone in my microwave oven, closed the door and then called it from a landline. I expected the oven to shield it from the incoming microwaves, but to my surprise the phone rang. Does this mean the oven is tuned or that it is leaking?
Tam Anderson
Kirkcaldy, Fife, UK
Don鈥檛 bee late home
The other day I noticed a large bee enter the door of my train carriage. Later, I saw it depart at a station 10 miles further down the line. Is it likely the bee could find its way home, without using the train? If not, could it integrate into a new hive or colony, or would it face resistance and attack?
Chris Ball
By email, no address supplied