High Nitrate NO3-N level concern

Water report said

Nitrate 5.1 (most in this forum are under 1)
Sodium 10
potassium 1
calcium 31
Mg 6
CaCO3 103
SO4-S 5
Cl 3
CO3 <1
HCO3 84
tot alk 0.21
iron <0.01
pH 7.8

Everything looks pretty good except for the Nitrate level. It is from a well. I suspect agriculture related issues are causing the increase in Nitrate. No off taste that I can tell but if I use water from the fridge filter it does taste very slightly better. Is this level a concern for brewing? Is there a way to remove some of the Nitrate if needed? Should I just relax and keep brewing? And no slam to agriculture, it brings us food, clothes, medicine, beer etc

The limit is 10 and that is to protect infants who, exposed to nitrite (to which nitrate can be converted by some bacteria) may be harmed. As an adult you can tolerate levels much higher than this. Nitirite is no so good for yeast either and there is risk, in high nitrate water, of this same bacterial reduction. But 5.1 as nitrogen is only 23 mg/L as nitrate and not something you need to worry about. If you wish to anyway note that a 1:1 dilution with RO/DI water would cut the nitrate to 12 mg/L and reduce the alkalinity to 51 - a good thing. 2:1 would be even better wrt the alkalinity and knock the nitrate down to 7 (or 1.8 as N which is approaching the 1 you seem to feel comfortable with).

Was your report labeled 'SAFE' next to the nitrate number?

As AJ pointed out for me a few months ago, nitrate as nitrogen (NO3-N) is 10 ppm or less in potable water. That is equivalent to 44 ppm nitrate that is actually reported as nitrate! Looks like the OP is OK.

Ward Labs report said Nitrate 5.1 SAFE. I am happy about the safe, it was the beer I was worried about. Mixing 1:1 with RO/DI water is easy enough. My mash gets to 5.2 to 5.4 ish depending on who is looking at the color strip. So maybe I will try 2 different 3 gallon batches of the same beer with my well water vs a 2:1 mix. Any suggestion on what style would make the difference more apparent. Also, should I skip the DAP addition to the end of the boil or is the nitrogen compound different enough. (I did get an A in college organic chemistry but it was 30 years ago).

I would have expected it to say SAFE for any value less than 10 and did understand that your concern was for the beer. I asked the question mostly to confirm that your water report came from Ward Labs which I suspected because the sulfate was listed as sulfur but some of the other numbers don't make sense. Ward Labs doesn't list bicarbonate, your bicarbonate number is about what your alkalinity should be and alkalinity of 0.21 doesn't compute because even deionized water has alkalinity higher than that.

Moll wrote (Handbook of Brewing, first edition) that the upper limit for nitrate is, depending on the author, 20 - 50 mg/L (as Nitrate), and you are edging into that region. I still don't think that you need be concerned but RO water is a strategy for you nitrate or no.

With a 2:1 dilution your water is 'soft' enough to allow you to use the recommendations of the Primer in the Stickies here. Follow them and you should be on the way to good beer in almost any style except for some of the dark ones where things get a little trickier. The benefits of low mineral beer are best appreciated in delicate lagers and ales such as Kölsch.

As for the DAP it can't hurt within reason. I assume you are using a pre-packaged nutrient and not just straight DAP. If not I'd recommend one of those as they usually give you a bit of zinc into the bargain and zinc is one mineral that the malt doesn't seem to contain much of.

Nitrate at that low level is not going to effect taste at all.

My well water is coming from a 360' well but I still have Nitrate of 5.9 ppm in mine which is safe and honestly surprised me it was that low considering that upslope of my house is 1,000 acres of corn/soybean field!

Great info. Very grateful for the support and information.

Your water comes from an aquifer fed by the Appalachians. No runoff from those fields should be entering you well.

ajdelange said:

Your water comes from an aquifer fed by the Appalachians. No runoff from those fields should be entering you well.

Click to expand...

The reason Nitrate (NO3) is a ground water problem is because the Nitrate ion does not bind to soil particles (negative charge) and leaches as a soluble with the rainwater into the groundwater table. My well may be 360' deep but my free water is at 15' so it is inevitable that agriculture and possibly septic systems will cause some detectable levels of Nitrate in well water.

How does the water at 15' penetrate the 345' of limestone?

I'm tapping the same aquifer (AFAIK) as you are and I have 4.7 mg/L as N (or at least did last time I measured it) and don't live anywhere near agriculture. Other folks around here whose water I have checked have similar levels and they all live in suburbia.

?

Most rock formations are fractured and fissured. Limestone can also be solutioned which produces conduits.

Yes but that's a lot of limestone and doesn't explain why everyone on that aquifer has about the same level of nitrate (which is about the same as but higher than the Potomac's). One USGS study I quickly found shows that the deeper the well the less nitrate makes it through - unsurprisingly enough. I'd buy the argument that some nitrate would make it through 300' of stone but I'm betting that in this case it is nitrate bearing rock that is mostly responsible. Surface water - yes, fertilizer doubtless has something to do with that but with deep wells it has to be less so. It is interesting here that I measure the nitrate in the river at less than that in the wells. These are spot measurements of course and should not be regarded as anything more than that.