How to calculate PPM as it pertains to mead/beer/wine

So, the question about PPM always seems to come up so I decided to write down my thoughts on the matter. I hope this helps everyone reading...



First thing is PPM means Parts Per Million. Parts Per Million...hmmm. Let look at a percentage for some context. One percent (1%) means 1 part per hundred or one hundredth (0.01). So 1 PPM means one part per million or one millionth (0.000001).

Second thing is PPM is a unit per unit measurement. Meaning you can't really say use liters and grams or cups and ounces. You need to use grams per gram, ounce per ounce, liters per liter, gallons per gallon, etc...

In the context of water at least, all this is the same as saying milligrams(mg) per Liter. Let me show you how I got there:

• 1 ml of water weighs ~1 gram. This is a fact. Water has a Specific Gravity of 1.000 so that means 1ml of it has a mass of 1 gram. 
• 1 Liter of water = 1,000ml = 1,000g 
• 1 mg (milligram) = 0.001 grams 
• So if there is 1mg (0.001g) of some substance in 1 Liter (1000g) of water then there is 1PPM (0.001g/1000g=0.000001) 

So let's go for some examples...

You have 1 liter of water and add 10g of sugar to it. What how many PPM of sugar did you add?

• You added 10g of sugar and that is = 10,000mg of sugar (1g=1000mg) 
• So now we now that PPM is the same thing as saying how many mg per liter. 10,000mg/1 Liter = 10,000 PPM. Easy right? 

Let's make it harder. You have 5 gallons of mead brewing and you have added 13g of Citric Acid. How many PPM of Citric Acid did you add?

• 5 gallons = 18.93 Liters (Google Conversions) 
• 13g of Citric Acid = 13,000mg 
• PPM = 13,000mg/18.93L = 686.74 ppm 

You can also work this all in reverse. So you again have a 5 gallon batch of mead brewing and you want to add 100ppm of Citric Acid.

• 5 gallons = 18.93 Liters (Google Conversions) 
• Rearrange the equation so XXXmg=PPM * Liters. Then we have Citric Acid mg=100ppm * 18.93 Liters = 1893mg of citric acid. 
• Convert to grams = 1893mg/1000=1.893 grams of Citric Acid are needed in a 5 gallon batch to get 100ppm. 

One more time... 20 Gallon batch and you want 324ppm of bentonite!

• 20 Gallons = 75.7 Liters 
• Bentonite mg = 324ppm * 75.7 Liters = 24,526.8mg = 24.5268g of Bentonite... 

Like a scrotum that's it in a nutshell.