Unit 4 - Lesson 3 - Molasses Flashcards
Describe a light rum?
Delicate and subtle flavors
Fermentation is different from heavy rums
What are the typical still associated with light rum?
Column
What is key for Yeast Selection in Light Rum?
- High ABV yield
- High Tolerance for temps 32-34°F (up to 37°C)
- Tolerance for Osmotic Stress
- Low Congeners production eg flavors
- High invertase activity
Why use pure yeast cultures in molasses fermentation?
Low microbial contamination so these bugs dont compete with yeast
What is the process of adding yeast to molasses fermentation?
It is first propagated in a pre-fermenter vessel.
The molasses is refilled in pre-fermenter to repeat process
What happens with Flocculating yeast strains
Sometimes these yeast are recycled from one fermenter to another
What is the process of recycling yeast?
Yeast is:
- Treated and conditioned with ACID WASH
- Added back to fermenter
- Sometime the acid wash they use penicillin to kill bacteria
Why acid wash yeast?
Reduce bacteria count when recycling yeast
How is recycled yeast collected?
Flocculation or Centrifuge from fermented wash
What is the typical usage period of recycled yeast in rum before replacement?
2 - 6 months
Why does recycling yeast work with molasses?
Can start rapid fermentation since there is enough yeast cells ready to go even with 22° Brix
And allows distillery to keep 2-3 fermentations going
What type of commercial yeast is used in rum distillation?
Dried yeast
- Can be added directly
- Can Propagate in pre-fermenter
- Longer shelf life (~3 years)
Process for light rum fermentation?
- Rapid
- no micros
- Good ABV yield
- Good flavor compounds
- Temp monitor
What is an example of unwanted compound in light rum?
sulphurous compounds - big flavor impact in small amounts
How are sulphurous compounds formed in light rum fermentation?
Yeast autolysis when temps get too high
Why have a temperature limit in light rum fermentation and what is it?
To reduce yeast autolysis which creates sulphur
28°C - 33°C
How do distillers prevent bacteria in molasses fermentation
- Penicillin
- Chlorine Dioxide
- Quaternary ammonium compounds
What is focus for light rum production?
Clean and fast fermentation
Limit bacteria and congeners
What micros are used in Heavy Rum production?
- Natural yeast
- Dunder
- Schizosaccharomyces pombeyeast
- Saccharomycescerevisiae
- Clostridium saccharobutyricum
Where are heavy rum typical distilled in?
Pot stills
Sometime column
Why use Spontaneous Fermentation in. Heavy Rum production?
Keeps costs down & complex flavors
BUT can cuse low fermentation efficiency and yield
Not always the same flavor - bacteria and yeast are different batch to batch
What is dunder?
Dunder is the yeast-rich foam leftovers from one batch of rum that is used to start the yeast culture of a second batch
Why add bacteria to fermentation?
Creates acids that produce esters leading to complex flavors
What the types of acid bacteria create in Heavy Rum?
acetic acid, propionic acid and butyric acid
