Citric Acid:
While citric acid readily found in citric fruits, citric acid is produced on a production scale via fermentation of various sugars. 

Market Dynamics:
Because corn is a readily available source of carbohydrates in the US, citric acid is fermented from corn related sugars/carbohydrates using Aspergillus niger. This makes citric acid and  vulnerable to natural disasters and fertilizer fluctuations. 

Up Stream Materials/Building Blocks:
​ Aspergillus niger 

Carbohydrate (Corn, Molasses, Sucrose, Glucose, Fructose)

Calcium Hydroxide 

Down Stream Materials Consuming  Citric Acid:

​Food additive, usually for flavor or as a preservative

Buffering agent 

Boiler descaling

Chelator