Nitrates in water

[The-Engineer-That-Brews]

Read this today, in a doc from Murphy & Sons:

Levels of Nitrate are beginning to drop generally due to greater control of the use of nitrogenous fertilisers. Nitrates themselves are not a problem at levels below 50 mgs/l, however they can be reduced by yeast or bacteria to form Nitrites. These ions can then react with wort amines to form Nitrosamines, which are carcinogenic.​

Ooooofff - that's not good... my water report indicates nitrate levels at about 30mg/l which seems about typical for most UK supplies. I hope that doesn't translate into significant levels of 'nasties'

 

[moto748]

<hurriedly checks water profile>

Nitrate levels >2.65, it says, legal limit 50 mg/l.

Phew!

 

[The-Engineer-That-Brews]

<hurriedly checks water profile>

Nitrate levels >2.65, it says, legal limit 50 mg/l.

Phew!

Yeah - but did you read the second bit... nitrates themselves are not a problem below 50 mg/l - BUT yeast/bacteria con convert them into nitrites which then react with the wort to make cancer-causing nitrosamines.

Therefore I'm not going all paranoid - I'm just not sure what would be a safe level of nitrates in water that's going to be used specifically for brewing...

 

[The-Engineer-That-Brews]

@DocAnna any view on the toxicology of nitrosamines?

 

[DocAnna]

@DocAnna any view on the toxicology of nitrosamines?

Thanks for the tag. As a bit of a pre read and de-escalation of concern I suggest this (PDF) Reduction of Nitrosamines in Beer - Review of a Success Story
The main sources of nitrosamines in the diet are through processed meats :bacon, sausages, and particularly smoked meats Dietary Nitrates, Nitrites, and Nitrosamines Intake and the Risk of Gastric Cancer: A Meta-Analysis. In terms of beer, the main risk of forming nitrosamines is with direct malted grains, ie flame malted including the smoke. Nitrates in themselves are a low risk and would require bacterial or heat transition to nitrite, which is not part of fermentation or the boil process, as the conversion requires reactive nitrogen oxides formed during high temperature burning - ie gaseous fumes reacting with the malt Error - Cookies Turned Off , though to be fair bacteria can also form nitrosamines reacting with nitrate rich foods in the mouth Formation of nitrosamines during consumption of nitrate- and amine-rich foods, and the influence of the use of mouthwashes - PubMed and it was thought that the acidic conditions in the stomach contributed adversely to nitrates to nitrosamine metabolism. However more recent studies have backed up the cardiovascular protective value of nitrate in the diet Nitrate and Nitrite in Health and Disease .

Ok the short version.

• If you have a spoiled beer with bacteria then it's not a great idea to drink lots of it....(you don't say!)
• Nitrates in water ... not anywhere close to a risk factor for nitrosamines.
• Main risk in beer used to be open flame malting - not done any more so dinnae fash
• The whole nitrate =bad argument is not really valid
• nitrosamines are highest in bacon, sausages, other processed meats are the biggest source of risk of nitrosamines, and intake is already recommended to be limited https://www.iarc.who.int/wp-content/uploads/2018/07/pr240_E.pdf, Meat in your diet for a more readable version see : How much meat is safe to eat?

So drink beer and be happy that at least the nitrates in the water are the least of your concerns.
.....though the alcohol is a different matter...

Anna

 

[RoomWithABrew]

Maybe this is the way to go, whole recipe only for subscribers. But sounds a delicious idea having read it.

https://beerandbrewing.com/brewing-with-bacon-including-a-recipe-from-uncommon-brewers/
Shame to see that Murphy & Sons have no idea about units,

Read this today, in a doc from Murphy & Sons:

levels below 50 mgs/l,​

There appears to be a unit of time in here!

I suppose it depends on how fast the tap is running.

As Anna says the elephant in the room is this

https://www.cancer.gov/about-cancer/causes-prevention/risk/alcohol/alcohol-fact-sheet

 

[The-Engineer-That-Brews]

Thanks for the tag. As a bit of a pre read and de-escalation of concern I suggest this (PDF) Reduction of Nitrosamines in Beer - Review of a Success Story
The main sources of nitrosamines in the diet are through processed meats :bacon, sausages, and particularly smoked meats Dietary Nitrates, Nitrites, and Nitrosamines Intake and the Risk of Gastric Cancer: A Meta-Analysis. In terms of beer, the main risk of forming nitrosamines is with direct malted grains, ie flame malted including the smoke. Nitrates in themselves are a low risk and would require bacterial or heat transition to nitrite, which is not part of fermentation or the boil process, as the conversion requires reactive nitrogen oxides formed during high temperature burning - ie gaseous fumes reacting with the malt Error - Cookies Turned Off , though to be fair bacteria can also form nitrosamines reacting with nitrate rich foods in the mouth Formation of nitrosamines during consumption of nitrate- and amine-rich foods, and the influence of the use of mouthwashes - PubMed and it was thought that the acidic conditions in the stomach contributed adversely to nitrates to nitrosamine metabolism. However more recent studies have backed up the cardiovascular protective value of nitrate in the diet Nitrate and Nitrite in Health and Disease .

Ok the short version.

• If you have a spoiled beer with bacteria then it's not a great idea to drink lots of it....(you don't say!)
• Nitrates in water ... not anywhere close to a risk factor for nitrosamines.
• Main risk in beer used to be open flame malting - not done any more so dinnae fash
• The whole nitrate =bad argument is not really valid
• nitrosamines are highest in bacon, sausages, other processed meats are the biggest source of risk of nitrosamines, and intake is already recommended to be limited https://www.iarc.who.int/wp-content/uploads/2018/07/pr240_E.pdf, Meat in your diet for a more readable version see : How much meat is safe to eat?

So drink beer and be happy that at least the nitrates in the water are the least of your concerns.
.....though the alcohol is a different matter...

Anna

Fantastic! Many, many thanks @DocAnna that‘s precisely the type and quality of info I was looking for - thank you so much :hat:
Perhaps I’d better skip the fry-up breakfast this morning then!