[header] How to simulate stomach acid [title] Use a cup of plain, white vinegar. [step] While vinegar is not as acidic as stomach acid, it can be used to simulate what a stomach does in a simple experiment. To use it, simply fill a cup with vinegar, and drop what you want to test into the cup. 
Vinegar ranks at about 2 on the ph scale, so it is about as acidic as stomach acid. [substeps] The acidity of stomach acid is usually in the range of 1 to 3 on the ph scale.