To produce approximately 1 jin (斤, 500 grams) of alcohol, it typically requires 2.5 to 3.5 jin of grains (such as corn, wheat, or rice), depending on the starch content and fermentation efficiency. Here’s a detailed breakdown:

1. Starch Conversion: Grains like corn contain about 65–75% starch. Through hydrolysis and fermentation, starch is converted into glucose and then into alcohol (ethanol).

2. Theoretical Yield: The chemical equation for fermentation is ( C_6H_{12}O_6 rightarrow 2C_2H_5OH + 2CO_2 ).

3. Practical Calculation:

At 46% practical efficiency: ( 350 ,

ext{g starch}

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imes 0.46 approx 161 ,

ext{g ethanol} ).

Thus, to produce 500 g (1 jin) of ethanol: ( 500 ,

ext{g} ÷ 161 ,

ext{g per jin corn} approx 3.1 ,

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ext{jin corn} ).

Summary:

This aligns with industrial data where 1 ton of ethanol needs 2.8–3.2 tons of corn (or equivalent grains).