Aged vinegar, generally the concentration is not high, because the nature of aged vinegar is to be consumed. The highest aged vinegar will not be higher than 10%, and the price should be under 5 dollars. The most common vinegar on the market is the "9 degrees vinegar", and only for this 9 degrees vinegar, when we eat it, we have to dilute it with water. Generally, vinegar with less than 5 degrees of acidity is called "food vinegar". Therefore, there is no such thing as "aged vinegar with the highest acid concentration of 20%". However, you can buy acetic acid to make your own vinegar, or buy vinegar essence, which is more in line with your requirements, 40 degrees of vinegar essence is more common, and you can dilute it by yourself. (Note: vinegar, vinegar diluted to meet the requirements can drink, acetic acid can not)