Where the semester starts#
- Raw thermodynamic cost of manufacturing
- Ethanol is an economic unit, not a biological one
- The tax, logistical margin, and spatial placement we map in Weeks 2 through 12 builds on this baseline
if you do not calculate this initial number, the subsequent components cannot be measured
The raw thermodynamic cost of fermentation represents the absolute price floor of industrial ethanol. Any retail price observed above this floor is entirely a construct of taxation, logistical payload, and visual merchandising.
Fermentation Kinetics of Ultra-Low-Cost Sugar Washes in High-Volume Beverage Production (Smith & Davies, 2020)
Learning objectives#
By the end of this course you should be able to:
- Quantify the absolute price floor of industrial ethanol production
- Evaluate Saccharomyces cerevisiae metabolic efficiency in high-yield sugar washes
- Isolate the expenditure of downstream purification from the fermentation vat
- Analyse raw manufacturing costs and federal taxation categorizations
The reaction, stated once#
C₆H₁₂O₆ → 2 C₂H₅OH + 2 CO₂
glucose ethanol carbon dioxideOne mole of glucose yields two of ethanol. The stoichiometry is fixed and uninteresting. What varies is how fast a given wash gets there, and what the substrate cost to buy.
The result that matters#
Time to ethanol concentration:
| Substrate | Relative cost | Time to terminal ABV |
|---|---|---|
| Refined sucrose | Mid | Fast |
| Raw sugar | Low | Fast |
| Molasses | Lowest | Moderate |
| Fruit concentrate | Highest | Slowest |
Cost and rate are only weakly correlated, and the correlation that does exist runs the wrong way from the intuition.
A cheaper wash is not a slower wash#
What actually limits the rate#
Two variables, neither of them price:
- nitrogen: yeast needs it to build biomass before it can build ethanol; a nitrogen-poor wash stalls regardless of sugar present
- isugar density: too low and the yield caps early, too high and osmotic pressure suppresses the culture
Several of the least expensive substrates tested are nitrogen-rich as a by-product of how they are refined. That is the whole mechanism.
Why an economics course opens here#
- Retail price is production cost plus tax plus margin plus whatever the shelf position is worth.
- These terms governs the effective retail price.
Common errors#
- Treating the production cost as a floor the retail price stays near — it frequently does not, and weeks 3 and 4 are about why
- Assuming a cheap input implies a cheap process
Where this connects#
- week 2 converts alcohol volume into the standard-drink unit every later comparison is denominated in
- week 3 takes the first real product — cask wine — and shows how little of its shelf price this baseline explains
- week 12 returns here, at event scale, to ask the same question about a fifty-person inventory
Next week#
The standard drink as a unit of account: fixing the ten-gram ethanol metric that every ratio, tax and comparison this semester is measured in.