DirtyPolock
Well-Known Member
So I don’t know if something like this exists somewhere else on the forum so my apologies if this is a duplicate. I want to try to explain why to not fear the foam via math.
Starsan has two active ingredients: Dodecylbenzenesulfonic acid (DDBSA) and Phosphoric acid (PA). Their concentration in straight starsan is 15% and 50% respectively. This means that for every mL of starsan there is 150 mg of DDBSA and 500 mg of PA.
If you mix up a 5 gallon batch of Starsan in your ale pail fermenter and use the recommended 30 mL of starsan then you have a total of 4.5 grams of DDBSA and 15 grams of PA per 5 gallons (18,927 mL) of water. This results in a concentration of 0.238 mg/mL of DDBSA and 0.793 mg/mL of PA in this mix.
At this point you will empty your ale pail before you add in your wort and yeast to make beer. After dumping your starsan batch you will have a little foam and diluted starsan left over. My guess is that you will have no more than 10 mL of this left in the fermenter and this is likely a stretch, but 10 mL makes for easy math. This means that there is 2.38 mg of DDBSA and 7.93 mg of PA left in your ale pail. At this point you will dilute it again with 5 gallons of your wort which will turn into beer. This results in the new concentration of 0.000126 mg/mL of DDBSA and 0.000419 mg/mL of PA.
Based on this concentration you will drink 0.0596 mg of DDBSA and 0.198 mg of PA in each pint of beer that you just fermented.
Well if I keg my beer and follow the exact same dilutions to sanitize my keg I would have double the amount that I just listed above (i.e. 0.1192 mg DDBSA/pint and 0.396 mg PA/pint). What does this mean in terms of toxicity? The lowest LD50 (dose where 50% of animals will die) for DDBSA that I could find was for a mouse which is 50 mg/kg. If I would need this same dose where I have a 50% chance of death I would need 5000 mg (5 grams) of DDBSA. This about 41,900 pints of beer that I draw from my keg.
The lowest reported lethal dose of PA for a human is 200mg/kg, which for me it would be 20000 mg (20 grams). For me this is around 50,500 pints of beer from my keg.
As there are only 40 pints in a 5 gallon keg so you can drink your entire keg before you get to the reported lethal doses of the starsan agents. You would die from fluid over load (low sodium) or acute alcohol toxicity if you would drink your entire keg in a sitting before you have problems with the left over starsan.
If you leave less than 10 ml of diluted starsan your fermenter or keg then you need to proportionally increase the numbers of beer that you need to drink to reach your limit. If you leave 5 mL in your fermenter then I would need to drink twice the number of beers that I listed above…2mL’s in my fermenter then 5 times the number of beers that I listed above, etc., etc., etc.
Well I hope that this helps to calm any fears regarding the left over starsan solution in your fermenters/bottles/kegs. Now I need to start working on drinking some beers and get close to my limit.
Starsan has two active ingredients: Dodecylbenzenesulfonic acid (DDBSA) and Phosphoric acid (PA). Their concentration in straight starsan is 15% and 50% respectively. This means that for every mL of starsan there is 150 mg of DDBSA and 500 mg of PA.
If you mix up a 5 gallon batch of Starsan in your ale pail fermenter and use the recommended 30 mL of starsan then you have a total of 4.5 grams of DDBSA and 15 grams of PA per 5 gallons (18,927 mL) of water. This results in a concentration of 0.238 mg/mL of DDBSA and 0.793 mg/mL of PA in this mix.
At this point you will empty your ale pail before you add in your wort and yeast to make beer. After dumping your starsan batch you will have a little foam and diluted starsan left over. My guess is that you will have no more than 10 mL of this left in the fermenter and this is likely a stretch, but 10 mL makes for easy math. This means that there is 2.38 mg of DDBSA and 7.93 mg of PA left in your ale pail. At this point you will dilute it again with 5 gallons of your wort which will turn into beer. This results in the new concentration of 0.000126 mg/mL of DDBSA and 0.000419 mg/mL of PA.
Based on this concentration you will drink 0.0596 mg of DDBSA and 0.198 mg of PA in each pint of beer that you just fermented.
Well if I keg my beer and follow the exact same dilutions to sanitize my keg I would have double the amount that I just listed above (i.e. 0.1192 mg DDBSA/pint and 0.396 mg PA/pint). What does this mean in terms of toxicity? The lowest LD50 (dose where 50% of animals will die) for DDBSA that I could find was for a mouse which is 50 mg/kg. If I would need this same dose where I have a 50% chance of death I would need 5000 mg (5 grams) of DDBSA. This about 41,900 pints of beer that I draw from my keg.
The lowest reported lethal dose of PA for a human is 200mg/kg, which for me it would be 20000 mg (20 grams). For me this is around 50,500 pints of beer from my keg.
As there are only 40 pints in a 5 gallon keg so you can drink your entire keg before you get to the reported lethal doses of the starsan agents. You would die from fluid over load (low sodium) or acute alcohol toxicity if you would drink your entire keg in a sitting before you have problems with the left over starsan.
If you leave less than 10 ml of diluted starsan your fermenter or keg then you need to proportionally increase the numbers of beer that you need to drink to reach your limit. If you leave 5 mL in your fermenter then I would need to drink twice the number of beers that I listed above…2mL’s in my fermenter then 5 times the number of beers that I listed above, etc., etc., etc.
Well I hope that this helps to calm any fears regarding the left over starsan solution in your fermenters/bottles/kegs. Now I need to start working on drinking some beers and get close to my limit.