Category Archives: Process

A look at the Beer Brewing Process – Just in time for the Rotronic 2014 International Sales Meeting

Beer brewing in general

There is no exact date, as to when the first beer was brewed but already at the beginning of the fifth millennium BC, people in southern Mesopotamia, in a region known as Sumer (modern Iraq), were brewing beer.

Beer, like other commodities such as wheat and other grains, was used as a currency. A clay tablet, dating from 6’000 BC contains one of the oldest known beer recipes.

Beer Map
Beer consumption throughout the world

The basic ingredients of beer are: water; a starch source: which is able to be fermented; yeast: to produce the fermentation; a flavouring such as hops. Yeast is the microorganism that is responsible for fermentation. Specifically Saccharomyces cerevisiae is the species of yeast that is used for brewing.

Facts & figures:
Beer is the third most popular beverage in the world, coming in directly behind tea and water.
American beer is made mostly from rice. This was invented to give American beer a lighter taste and tap into the market of women buyers.
In the UK 28 million pints of beer are consumed every day, which equates to 100 litres per head each year.
Belgium has over 400 different beer brands.
Cenosillicaphobia is the fear of an empty glass.

There are several steps in the brewing process, which include malting, milling, mashing, lautering, boiling, whirl-pooling, fermenting, conditioning, and filtering.

Step by step brewing:
  • Malting: germination of cereal grains. The sprouted cereal is then kiln dried at around 55°C. Milling: grinding of the malted cereal.
  • Mashing: the cereals are mixed with water and then heated.
  • Lautering: separation of the mash: the liquid (wort) is separated
    from the residual grains.
  • Boiling: the wort is boiled to ensure sterility and then hops are added for flavour!
  • Whirl-pooling: the wort is sent into a whirlpool, removing the dense particles using centrifugal force.
  • Fermenting: yeast is added to the wort: conversion of the carbohydrates to alcohols and carbon dioxide – the chemical conversion of sugars into ethanol!
  • Conditioning: the tank is cooled and the yeast and proteins separate from the beer. This conditioning period is also a maturing period.
  • Filtering: the beer is filtered: stabilising the flavour.
  • Packaging: the beer is packed then to the customers
Example brewing process
Example brewing process
Why the need to measure the carbon dioxide?

Carbon dioxide Carbon dioxide (CO2) is a naturally occurring chemical compound. It is a gas at standard temperature and pressure.

We inhale oxygen and exhale carbon dioxide. The carbon dioxide level in exhaled air is rather constant: around 3,8%. When carbon dioxide is exhaled it will quickly be mixed with the surrounding air even indoors and provided that the ventilation is good, the concentration will be reduced to harmless levels. Indoor carbon dioxide levels usually vary between 400 and 1’200 ppm (parts per million). Outdoor carbon dioxide levels are usually 350 – 450 ppm.

Beer brewing process: Heavily industrialised or contaminated areas may periodically have a higher concentration of CO2. Carbon dioxide is released during the beer brewing process and as you will see below, CO2 is toxic for living organisms. In brewery environments where process generated carbon dioxide is widely present, the maximum permitted carbon dioxide concentration according to most standards is as high as 5’000 ppm (5%) during an 8 hour working period.

Beer storage: Most beer leaves the brewery carbonated: beer and carbon dioxide are sealed in a container under pressure. It can be carbonated during fermentation but it can also be carbonated in the bottle. In this case the beer is allowed to ferment completely. It is left unfiltered which leaves active yeast suspended in it. A small amount of sugar is then added at bottling time. The yeast begins to act on the sugar: CO2 is released and absorbed by the beer.

Beer can also be force carbonated, in which case it is allowed to fully ferment. Then CO2 is pumped into a sealed container with the beer and absorbed by the liquid. In this case, a tank of carbon dioxide will also be required. Undetected leaks in a gas system is a costly waste and a safety risk to personnel. While small leaks are inherent in any gas system, those of significant size raise the level of economic and safety risk.

How does CO2 affect the human body?

Due to the health risks associated with carbon dioxide exposure, there are regulations and laws in place to avoid exposure! The US National Institute for Occupational Safety and Health (NIOSH) states that carbon dioxide concentrations exceeding 4% are immediately dangerous to life and health.

In indoor spaces occupied by people: concentrations higher than 1’000 ppm will cause  discomfort in more than 20% of occupants. At 2’000 ppm, the majority of occupants will feel a significant degree of discomfort and many will develop nausea and headaches.

How CO2 affects the body
How CO2 affects the body

Case study: The lake Nyos
The lake Nyos is a crater lake situated in Cameroon. In 1986, a pocket of magma from under the lake, leaked a large amount of CO2 into the air. The result was suffocation of around 1’700 people and 3’500 livestock!

As we take beer brewing seriously we will be sure to test a number of varieties with our colleagues from the world over at the Rotronic 2014 International Sales meeting in Grindelwald next week!

Dr Jeremy Wingate
Rotronic UK

“Humidity & Temperature Sensors Help Cheese Taste Just Right” GUEST BLOG POST by THORNE & DERRICK

Thorne and Derrick have written a great blog post on the importance of quality measurement and control in cheese manufacturing (a key industry for Rotronic sensors due to their reliance to the high humidity conditions in cheese maturing!) 

Check out the post here…

Humidity & Temperature Sensors

Thorne and Derrick are national distributors and worldwide exporters of process & mechanical equipment. 

 

Would you like us to share your blog posts on measurement or humidity? Please contact us!

Dr Jeremy Wingate
Rotronic UK
jeremyw@rotronic.co.uk

 

The Great British Bake Off… It’s all about humidity!

Bread – The stuff of life!

Most of us have a never ending choice of the most delicious breads, cakes and pastries to please both the palate and the eyes. We have become so used to this diverse range of bread and baked products, but do you how bread originally came into existence?

The interesting history of  what is now called the “staff of life”, bread, and the making of it, started in comparatively recent times.

At the very beginning of recorded history there was the discovery of fire making and thus along with light, heat could be generated. Then it was found that different grasses and their seeds could be prepared for nourishment.

Later, with the combination of grain, water and heat, it was possible to prepare a kind of dense broth. Hot stones were covered with this broth or the broth was roasted on embers and “hey presto” the first unsoured flat bread was created. This ability to prepare stable food radically changed the eating habits and lifestyles of our early ancestors. They progressed from being hunters to settlers.

Facts & figures:

  • Records show that as early as 2600-2100 B.C. bread was baked by Egyptians, who it is believed had learned the skill from the Babylonians.
  • On average, every American consumes around 53 lb (24 kg) of bread per year.
  • The “pocket” in pita bread is made by steam. The steam puffs up the dough and, as the bread cools and flattens, a pocket is left in the middle.
  •  US Farmers receive just 5 cents (or less) for each loaf of bread sold.

Why the need to measure humidity?

The production of baked goods such as bread, cakes, biscuits and pastries requires a number of processing steps in which humidity and temperature play an important role.

After mixing, it is typical to divide the dough into pieces and allow it to rest for a few minutes so that the gluten network in the dough can relax allowing easier moulding, which is the next step.

If at that stage, the temperature is too hot the dough will be too sticky and cannot be easily processed further, if too cold the dough can become damaged during moulding which leads to holes forming in the bread. If the humidity level prior to the moulding process was too low a skin of dry dough can form on the dough surface. This makes it harder for the dough to increase its volume during the next
process step called proving.

Proving is the professional term for the final dough-rise step before baking, where 90% of the bread volume is achieved. To achieve consistently good dough rising results special chambers are used. These chambers can maintain the ideal environment for the yeast to grow. Depending on the yeast and flour used, temperatures between 38…42°C and humidity levels between 70…80%rh are considered ideal.

In summary, the use of quality ingredients and careful handling throughout the various stages of production will not result in a quality product  unless the dough temperature, and the temperature and humidity of the bakery are carefully regulated. Modern day bakeries use custom ventilation systems that are controlled by precision humidity and temperature sensors.

So once again the behavior of the humble water molecule is to blame! In this case for the stricken faces of The Great British Bake Off contestants as they stress about the quality of their crust and whether the dough will be cooked through to perfection!