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Brewing with Rain Water?

After five years of brewing on a stove, splitting five gallon batches into two pots on the stove, I’ve got a propane burner and a new ten gallon pot, so brewing is moving out doors. We’ve got a lot of chlorine in our water (and we pay for it), so I had what I might be a brilliant thought. We have two rain barrels at our house. Would it be nuts to brew with that? Is there any way of determining how or if it should be treated for brewing short of getting it tested?

My thinking is that whatever it is, it’s likely to be better that the city water.

What do you guys think?

Got shingles on your roof?
Petroleum products in those.
Metal roof?..If you have a way to let the first 10 minutes of rain “clean” the roof, then gather your brewing water.

But above all this, have it tested…If not so much worried about the mineral content of it, have it checked at your county water authority.

Others will chime in with the actual science as this has been brought up many, many times before.
The general thought was that bacteria and other contaminants like chemicals will be literally sky high. Rain water or other collected runoff is called “gray” water for a reason. Perfectly fine for washing, gardening, flushing toilets etc… Drinking not so much.

You are thinking the exact opposite of what is reality. You would think rain water would be more “clean” than municipal supply, when in fact municipal is by far more consistent and clean and the only reason not to use is really hard water with high alkalinity. Chlorine/ chloramines are not a concern. Ever heard of campden? (potassium metabisulfite) or if you want to go extreme use an activated charcoal filter. Sunlight also works. My municipal is always close to the max allowed by the EPA and with the use of campden I never have issue and my beers are always on point.

Don’t use it there are so many bad things in rain water you don’t even want to know.

I asked this same question about 12 years ago and was told never to use it because of acid rain amongst other things.

Even if acid rain is not a concern in your area, you should be aware of something called “dry deposition.” Essentially, many acidic compounds are deposited either in salt form, or along with dust as it is deposited from the atmosphere. So, along with mold spores, wild yeast, soot and ash, you have acidic dust on your roof. I’d skip it for sure.

If you’re looking for better water for brewing, you should consider using spring water or reverse osmosis. I buy RO water from Walmart or the grocery store for about 35 cents a gallon. For a typical batch, I use about 8 gallons of water. I think $2.50 is a small price to pay for water, since that’s the majority of what beer is.

This comes up more often than it should. Do people really have that much rain water? I’d be hardpressed to gather the 10 or so required gallons for an all grain batch.

Think of all the creatures that fly over your roof and let loose. :shock: Those shingle are made with oil, so pretroleum products are most likely washed off. Better to use your local water or build your own.

I have a fifty gallon barrel that fills up pretty fast from just a portion of my roof, but we tend to get storms that drop an inch of rain in a couple of hours.

I also found dead squirrel in it while winterizing. Probably not the best source for brewing water.

I tested the ph of my rain water last night and it was ph 5.4 :shock:

Rain water is fine for brewing usage. Do recognize that it will contain impurities and is not really safe for drinking without treatment. However, the brewing process does make water safe for consumption. A consideration everyone should recognize is that all water was once rain water and any of those sources could be similarly or more contaminated than the roof drainage may be. Those of you with water utilities getting their water from rivers or reservoirs should understand that your water has run across every filthy thing you can imagine on its way to you. Modern treatment processes are capable of cleaning that water to potable quality.

Most water treatment plants DO NOT remove dissolved constituents like organic compounds (like the roof tar example above) and metals (zinc from a metal roof), so its a foolish assumption that tap water is automatically better. The thing we can count on with our tap water is that it is sanitary and relatively free from hazardous levels of a variety of contaminants. With that said, the advice to collect water after the first flush of a rain storm is wise. That will wash away a large percentage of contaminants. There are millions of homes that rely on roof catchment and cisterns for their water. Minor treatment is all that is required to make that water safe to drink. But it is already safe to brew with.

Brew on!

Dissolved CO2 in the water is the main culprit. It would make carbonic acid, H2CO3.

[quote=“mabrungard”]Rain water is fine for brewing usage. Do recognize that it will contain impurities and is not really safe for drinking without treatment. However, the brewing process does make water safe for consumption. A consideration everyone should recognize is that all water was once rain water and any of those sources could be similarly or more contaminated than the roof drainage may be. Those of you with water utilities getting their water from rivers or reservoirs should understand that your water has run across every filthy thing you can imagine on its way to you. Modern treatment processes are capable of cleaning that water to potable quality.

Most water treatment plants DO NOT remove dissolved constituents like organic compounds (like the roof tar example above) and metals (zinc from a metal roof), so its a foolish assumption that tap water is automatically better. The thing we can count on with our tap water is that it is sanitary and relatively free from hazardous levels of a variety of contaminants. With that said, the advice to collect water after the first flush of a rain storm is wise. That will wash away a large percentage of contaminants. There are millions of homes that rely on roof catchment and cisterns for their water. Minor treatment is all that is required to make that water safe to drink. But it is already safe to brew with.

Brew on![/quote]

Interesting. Would it be wise to boil the water before using it in the mash? Capden perhaps? Or would it be unnecessary because it would be later boiled as wort (is that the reason it’s OK for brewing)? I’d imagine the rain water could be better quality depending on where you live. Here in Oregon, it must be better than most, and it rains A LOT.

I don’t think testing it would be beneficial, because I’d imagine the water composition would change every time it rained depending on where it was evaporated or the conditions of any given day. Is this a sound assumption?

As always, thanks for your input.

Yes, they do…I have a 100 gallon Horse trough under one downspout, and 2 55 gallon drums lying horizontally, in series under another…PLENTY of water for any gardening needs, and they fill up FAST!
There a re 3 “untapped” downspouts on the front of the house!

The roof contaminants, I mentioned, hence , pass on the “first flush” of your roof.
Me personally, I would forgo the water from an asphalt shingled roof, but a metal roof, no problem…Just forgo the “first flush”.

Throw a 5 gallon bucket under one of your downspouts next time it rains, and time it to full, then multiply by number of downspouts, and duration of the rain…You’ll be amazed.

And on your domestic water bill, is there a charge for “storm water abatement” or the like?
There is on mine, and they figure it by the sq. footage of your roof…I had the peoples from the “Water Authority” out to see MY attempt at “storm water abatement”, and got a 20% reduction on that particular bill addition, even though my catchments fill and overflow.

It’s makes one hell of a reservoir for pre-cooling water, prior to using some ice water and a CFC.

And think of all the peoples in the Caribbean,Central and South America, who use rainwater as their sole source for cooking and drinking…Your going to boil the piss out of it anyway…Think of it as " Fully Organic Beer"… :cheers:

Save it , “ITsPossible”…You won’t change my mind… :slight_smile:

[quote=“S.Scoggin”]
Interesting. Would it be wise to boil the water before using it in the mash? Capden perhaps? Or would it be unnecessary because it would be later boiled as wort (is that the reason it’s OK for brewing)? I’d imagine the rain water could be better quality depending on where you live. Here in Oregon, it must be better than most, and it rains A LOT.

I don’t think testing it would be beneficial, because I’d imagine the water composition would change every time it rained depending on where it was evaporated or the conditions of any given day. Is this a sound assumption?

As always, thanks for your input.[/quote]

Preboiling is not necessary. Any microbes in the wort will be sterilized in the boil.

No need to analyze rainwater quality. It will bounce around as you say…from 0 to maybe 4 ppm in some ion concentrations. That IS a lot to worry about :wink:

I would consider water from an artesian well. I grew up on a farm and we had one and the water was awesome. Probably today they are bottling and selling it. I live in Georgia and don’t see to many of them here, but I’ll bet there are some in your area.

Agreed as to the boiling part on rainwater - we treated water by boiling on backpacking trips all the time, sometimes using a sweaty bandana as a prefilter and had no problems. The bugs are killed by the boiling and the sediment settled out. If collecting rain water, you might want to carbon filter it before using it in the mash to get the “bigger organic things” out. Also, a couple water department guys allow me to collect pretreated well water that they have available from a City well source (they know I am brewing with it). That water is from shallower wells they dug to mix with the deeper artesian wells to reduce radon found in the deeper wells. So maybe the rainwater isn’t such a bad idea after all?

If your municipal water supply is using chlorine rather than chloramine, consider yourself lucky. You can off-gas the chlorine by aerating it- no additional chemicals needed. I work at an aquarium and this is all we do for our fish.

If you are so inclined, consider gathering rain water to use for chilling. Of course it has to be cool, but you could use even ambient temperature water for chilling initially and then switch to tap later on. Would need a rain barrel and a pump, but none of it would need to be food grade.

To add some information on rainwater: Rainwater is generally very safe to use for cooking, but cleanliness is important. I brew exclusively with rainwater from a galvalume roof, food grade gutters, first flush system and months of settling out in a 2600 gallon food grade tank. My local tap water is super salty. Used it once, never again.

I like that almost every aspect of my brew system and process is scavenged, saved or renewable.

I’m not sure about this one… wells or water springs from certain geographic locations are rather better source

You need to figure out if it died from drinking the water or if it drowned. :wink:

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