|We all know that without yeast you can't make beer but did you realize that dry yeast is a practical alternative to
liquid yeast? Many brewers used to avoid the use of dry yeast due to its poor quality, but it has been greatly
improved.Yeast cultures are grown using a batch (all sugars are added at once while the yeast is fermenting) and
then a fed-batch system (the sugars are added slowly so that the yeast produces biomass and not alcohol) and
then dried using a fluidized-bed dryer (the yeast remains in suspension in warm air) which is gently on the yeast.
The production process is carefully optimized for each strain so that the yeast will recover and perform adequately
in fermentation once rehydrated according to the manufacturer's instructions. Because dry yeast is produced in
the presence of large amounts of air, there is no need for aeration/oxygenation prior to inoculation.
The quality of dry yeast has advanced because of extensive quality control put in place by the
manufacturers; viability and vitality measurements, contamination levels, and genetic integrity are among
tests being performed routinely.
There are numerous advantages to using dry yeast, the most important being a long shelf-life of up to 2 years.
It can be used as a propagation or pitched directly into fermentation and subsequently reused successfully
for many generations.
I've received a few question about a calandria in brewing. It is a tubular heat exchanger that heats wort quickly
and efficiently, enabling it to be boiled vigorously in the kettle. Wort requires a long vigorous boil, normally of 60–
120 minutes. Wort boiling releases bitterness from hops, reduces precursors for off-flavors such as dimethyl
sulfide, coagulates proteins, and renders the wort sterile. It is an expensive process because the energy costs
increase with each minute of boiling.
The calandria can be placed vertically inside a kettle or it can be external to the kettle and linked by piping and a
pump. In an internal calandria, convection forces the wort up through the vertical bundle of tubes, where it is
superheated by steam. When the calandria is external, the wort is pumped out of the kettle, through the calandria,
and then back into the kettle again.
Most kettle designs include a dish-shape wort spreader device that suppresses overfoaming, mixes the wort, and
drives off unwanted volatiles. A calandria provides a larger area for heating the wort than does a direct fired kettle
or those fitted with steam jackets.
The higher temperatures achieved using a calandria, typically up to 104.4°C (220°F) can reduce boil times
up to 30% while also increasing hop utilization in brewing systems using hop pellets.
Calcium sulfate is a critical component in the measurement of water hardness. Also known as non-carbonate
hardness, this part of water hardness is defined by the sum of all calcium and magnesium ions that are associate
with anions such as chloride or sulfate.It is referred to as permanent hardness because of the fact that it will not
precipitate under the influence of heat. Therefore, calcium sulfate is also one of the primary salts used for the
improvement of calcium levels in beer. Burton-on-Trent, England is the classic source of water with a high calcium
sulfate content, cause by the region's large gypsum deposits. The emulation of this classic water has lead to the
term "Burtonization," meaning to improve one's brewing water via the addition of calcium sulfate,
Hope you found this month's column of interest. If you have any questions about beer or brewing
or just want to submit a word for me to discuss here just e-mail it to me.
Thanks and Cheers!
|Yeast / Heat Exchanger / Calcium
|A new column by
|Jack O'Reilly attended the
famous Siebel Institute/ World
Brewing Academy in Chicago.
|I'm very excited to be part of the BeerNexus team. I think my many years in the
beer business both as a brewer and manger will enable me to explain and
investigate many topics of interest for those who really love craft beer.
Hope you join me every month.
More by Jack: #1, #2, #3, #4, #5, #6, #7, #8, #9, #10, #11,
#!2, #13, #14, #15, #16, #17, #18, #19