Brewing with tap water -- from the HOT faucet

[WBC]

I have not read all the posts from this thread but I do want to buy a tankless water heater that is adjustable (upper Limit) so that I can use it exclusively for brewing. If anyone knows of a certain brand and model that has this adjustment I would like to know about it.

 

[GNBrews]

This is the common wisdom, but it doesn't seem to make sense to me. If the minerals come out of the water to collect in the tank, then the water would then have LESS minerals that when it entered the tank. And if minerals collecting in the tank end up coming out in the water, then in a short time there would be no excess minerals in the tank.

It just doesn't make sense that water from the hot water tank would have more minerals than the water going in, unless it was somehow leaching minerals out of the metal of the tank itself.

You make a great point. I think what happens is that small amounts of sediment (very fine particles) are carried in the cold water supply, but remain undissolved because the water is cold. Since most of the water inside the heater remains there for a significant amount of time at higher temperature, the soluble portions of the sediment slowly dissolves into solution. Ideally, when the cold water is put into the boil kettle, the same dissolving process would occur, but I think the tank geometry and flow also plays a roll here. If the water inside the heater is being changed out at fairly regular intervals (do a few loads of laundry, family members take a few showers, etc. every day) I don't think there would be as much of a difference between the cold water TDS during a boil and what is coming out of the water heater. But, if the water is left sit for a few hrs (when you're sleeping, @work, etc.), then there might be a difference.

I have not read all the posts from this thread but I do want to buy a tankless water heater that is adjustable (upper Limit) so that I can use it exclusively for brewing. If anyone knows of a certain brand and model that has this adjustment I would like to know about it.

Whether or not it will work for depends heavily on the temperature of your incoming cold water supply. Most large units can only maintain a 55-60F temperature increase at a reasonable flow rate. The gas versions are better than the electric, but it was still a crapshoot when I compared the upfront cost with propane costs to just heat my HLT with a burner.

 

[Homercidal]

Ah, well I voted no based on using hot tap water AFTER the boil. Before boils is fine.

 

[ramz7887]

I orginaly was gonna do cold water only but my system is connected to the water lines so I spliced in hot water. I figured just to cut down on the time. I also added a carcoal filter before the hot water tank to clean up the water. The only problem is that since the water goes through the filter first it is not as cold as it was before.

 

[Malticulous]

I've used hot tap watter to mash in at acid or protein rests with hefeweizens and such, usually the start of a decotion mash. I've not noticed any problems.

 

[SpanishCastleAle]

I didn't read all the responses yet but my first thought was that it should be fine if it's hot water from one of those 'on-demand' water heaters but that there could be problems (depending on your water, water heater, and plumbing) if there is a tank involved. So...it depends..I think.

 

[smokey9015]

I have not read all the posts from this thread but I do want to buy a tankless water heater that is adjustable (upper Limit) so that I can use it exclusively for brewing. If anyone knows of a certain brand and model that has this adjustment I would like to know about it.

I have a Noritz N-0751 it will do up to 180*. It is nice it has a remote temp setting that I installed under my sink so if you want it hotter you go under the sink and turn it up or vise versa. The unit itself is in my basement. Just remember it will NOT be like a conventional hot water heater which means to get the H20 up to 180* it may cut the flow down so you only may get 1-2 gal/min out of it. If doing for the whole house make sure you have you have a large enough unit to supply the rating of your household in gpm for the unit for the h20 temp in the winder months. I do notice a slight difference in gpm between winter and summer. Other than that I love mine Saves $$$ on gas bill also.

One other point to keep in mind unless you have a battery backup installed on this you will not have hot water when the power is out.

 

[Poindexter]

I skipped pages and three and four, didn't vote. I have done just enough plumbing repair to make an ass/u/me/shun.

I think the minerals want to precipitate, but the water has to cool down for that to happen. In a relatively new system the minerals will be deposited evenly around the circumfrence of the hot water out pipe. In the fullness of time gravity will make a thicker deposit at the "bottom" of the horizontal piping.

I am thinking you might come from work on a weekday when no one has used any hot water for hours. Drain off the warm water in the pipes between your heater and faucet. Run however many gallons of fresh hot water into a tun, then let it cool over night.

The next day you might be able to siphon off the water and leave behind some precipitate. Otherwise I would think a mature system would offer "about" the same water chemistry as the cold tap does in the first place.

 

[BackAlleyBrewingCo]

I poured two cups of water - one from the cold tap and one from the hot, and let them both come to room temp. I didn't taste a difference in the two cups. I've been brewing with hot water ever since.

 

[dirtybear7]

I know this is an old tread but here is a helpful link

http://www.nytimes.com/2008/01/29/health/29real.html

 

[Dr. Francois]

I read through this thread and started getting REALLY scared...I made my baby's formula with a mixture of hot and cold tap water. I was worried he'd suddenly sprout flippers and wouldn't get into a good college. Well, maybe on a water polo scholarship.

So, I've spend most of the day bugging people I know who know about such things and reading online. Here's what I've learned about water safety and quality related to the hot water tap.

In addition to the MOUNTAIN of web articles warning me about future flipper babies, I found quite a few comments that most of the fears were grossly exaggerated.

Here's one such comment (from http://boards.straightdope.com/sdmb/showpost.php?p=2868120&postcount=20)

Well I talked to the prof today, and he explained things well enough that an actual test wouldn't even be neccesary to answer the question of "will hot water from the heater tank pose a threat to my health vs cold water?"... so sorry, no test results.

If your water has any alkalinity at all, you'll be more interested in learning the solubility of the metal carbonate salts rather than the metal it's self since that's how the metals will go into solution. Even so, with water 60C warmer sitting in your pipes, you might double or triple the metal's solubility in the water. The next thing you'd want to know is do you have lead pipes? Where I live they don't exist anymore, and even copper is on it's way out. If you do have lead pipes you shouldn't really be drinking any water flowing through them; worrying about how much more lead gets into the hot water from the tiney amount of contact time and length of unsuitable piping is sort of like worrying about whether you smoke light vs regular cigarettes - you're screwed either way.

The amounts of dangerous metals in proper piping are only present in trace amounts anyways, which shouldn't be dangerous... there's more potential for your water supply to have bad water at the source (which is regulated) than for it to become dangerously contaminated flowing through 15 feet of pipe for a few seconds.

And once again the scale you see in water tanks (mostly from calcium bicarbonate) has been precipitated out of your water during heating, hence this water has less of these minerals in it when it comes out the tap. And the reason it precipitates out is that the water cannot hold more than a certain amount of these minerals at the temperature it gets heated too, so it's not gonna pick up any extra when it flows through the heater tank. If your water is depositing minerals already, it's not going to pick up any more even if you dumped 50 pounds of it into the tank. Not to mention that calcium/magnesium carbonates and bicarbonates aren't going to hurt you anyways.

For that matter, neither will copper or iron in the amounts leached into a few feet of pipe - people purposely take all kinds of metal supplements daily. And to be picky, there will be one hell of a lot more metals leaching out of your pot or pan once you start frying or boiling at the really high temperatures than will come out of your water pipes at relatively low temperatures... and then we go scrubbing those metal pots nice and good afterwords to expose more new metal for the water to suck out next time, leave a bit of soap residue on them, and so on...

Lastly I measured the flow rate of my kitchen sink and the length of pipe between it and the water heater. There are about 15 feet of 1/2" copper pipe between the two, which holds a volume of 0.6L. The flow rate is 12L/minute. I also timed how long it took for the water coming out of the hot tap to "get hot" - 15 seconds.

So, at a flow of 12LPM, it takes 3.2 seconds for the entire volume of the heater-to-sink hot water pipe to clear, and by the time the water is hot enough for me to stick the pot underneath it, that volume has been replaced almost five times. The water going into my pot has a total exposure time of 5 seconds at 60-70C in those copper pipes. The metals that would have leached into it overnight are long gone before I even grab a pot to fill.

Disolved gases like chlorine will come out of solution faster from heated water, which most would consider good; even so the chlorine concentration is too low to be dangerous. Most of the bacteria that are human pathogens are mesophilic, dying off at temps above 45C... the thermophilic bacteria that may be in your water heater, if not already dead from the cold initial temps and chlorine throughout their stay, don't seem to be a problem either.

The guy I talked to has been a water chemist for the past 40 years, and a bit of an alarmist at that... anything even remotely dangerous he goes on and on about. When I asked him about this, he didn't even bat an eyelash and admits that he uses hot tap water to boil things faster himself. Ok, I think I've rambled on enough for now

Also, consider that if you have moderately hard water, the solder connections inside your pipes are covered very quickly by calcium and other deposits, making the risk of leaching negligible.

Our entire municipal water supply was transported through lead water mains. The city has been replacing the service lines over the last few years. A plumber friend of mine in the neighborhood commented that when they removed the lead service line, there was a 1" layer of calcium between the lead and the water, making absorption impossible.

I'd really like to use my 140 degree hot water to get a head-start on mashing, but I don't want to hurt anyone in the process. Just to be safe, I'm going to send my hot water to a lab to be analyzed. Maybe I'll do two samples: one fully-flushed cold water and one fully-flushed hot water.

 

[maltbarleyhops]

i use water from my hot water heater. ive plumbed a passive valve off the over flow. never had an issue with anything. i do have city supplied water with no softener. when i first considered this i tested cold vs hot water in my home and the only differences i came up with was temp. no additional minerals or solids. tested by Ecolabs.

 

[joeybeer]

I did the same thing as a few others, chilled a glass each of hot and cold water.. No taste difference, good to go ! Saves 45 mins !!

 

[Monkey-BB]

Screw this cold water.....I'm going hot hot hot

 

[Spartan1979]

Great response for opening a thread that's been dead three years. It added really useful info.

 

[dirtybear7]

I'm re-posting this link and article from the New York Times.

http://www.nytimes.com/2008/01/29/health/29real.html?_r=0


The Claim: Never Drink Hot Water From the Tap

"The claim has the ring of a myth. But environmental scientists say it is real.

The reason is that hot water dissolves contaminants more quickly than cold water, and many pipes in homes contain lead that can leach into water. And lead can damage the brain and nervous system, especially in young children.

Lead is rarely found in source water, but can enter it through corroded plumbing. The Environmental Protection Agency says that older homes are more likely to have lead pipes and fixtures, but that even newer plumbing advertised as “lead-free” can still contain as much as 8 percent lead. A study published in The Journal of Environmental Health in 2002 found that tap water represented 14 to 20 percent of total lead exposure.

Scientists emphasize that the risk is small. But to minimize it, the E.P.A. says cold tap water should always be used for preparing baby formula, cooking and drinking. It also warns that boiling water does not remove lead but can actually increase its concentration. More information is at www.epa.gov/lead or (800) 424-5323 (LEAD).

THE BOTTOM LINE

Hot water from the tap should never be used for cooking or drinking."

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It seems like in most cases it is a bad idea. If you have totally new plumbing that you know is 100% lead free in all areas you are probably ok.

Personally, I'd rather heat cold water and eliminated the risk of lead poisoning.