we never tested specifically for chloramine, but would routinely test for free chlorine in our water. Our municipal water varied quite a bit, but 0.9 mg/L was an annual average. Filtration through a GAC column filter reliably dropped that to 0.05 mg/L or less. Free chlorine in our hot liquor was usually 0.01 mg/L or not detectable.
The sensory impact of lowering free chlorine to =<0.05 mg/L was appreciable to untrained tasters: nobody here drank from the break-room faucet. Everyone would fill their water-bottles from the carbon-filtered cold-liquor line.
Original Message:
Sent: 03-05-2024 10:14
From: Travis Audet
Subject: Chloramine Removal - realistic goals?
Rob,
I took time to go through quite a few resources in an attempt to answer your question in regards to how much free chlorine/chloramine is too much and I could not find any. Unfortunately, it may come down to your process and how much free chlorine it can handle without impacting sensory. The answer to the question may have to do as much with the product being produced and the process.
For example, if the water in question is being used in the brewhouse and all of it is being boiled in the kettle then likely free chlorine levels can be higher as a large portion of the free chlorine will be driven off in the boil. Also, chlorine reacts much faster with ammonia than phenols so it is conceivable that chlorine would be more bound in the brewhouse where ammonia levels are higher than post fermentation where they are likely reduced by fermentation. (KINETICS OF CHLORINATION OF PHENOL - CHLOROPHENOLIC TASTES AND ODORS* G. FRED LEE and J. CARRELL MORRIS Int. J. Air Wat. Poll. Pergamon Press 1962. Vol. 6, pp. 419-431)
One of the reasons chloramines is used is it has better residual strength in the water distribution system. This is good news for drinking water quality but unfortunately it makes boiling reduction slower.
If the water being used is post boil/no boil or in high gravity brewing dilution then the levels would need to be lower. Waters that are for CIP rinse could be higher (within reason for stainless compatibility).
As I am sure you are already aware, the risk we are primarily concerned with is chlorophenol formation from chlorine interacting with the beer. The chlorophenols can have sensory impact on the beer.
One interesting thing is if you use a GC for diacetyl checks you can normally see a chloroform peak. The bigger this peak then likely the higher the chlorine/chloramine content the sample was exposed to.
Normally in activated carbon, we manage the Total Trihalomethanes (TTHM's). These are what form when chlorine/chloramine react with organics. Some of these reactants have very low flavor thresholds in ppt. Again, there is no agreed upon max limits for TTHM's likely because it may depend on the beer being made. I have seen a limits ranging from as low as 5ppb to as high as 20ppb TTHM in breweries post carbon treatment.
Hope this helps.
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Travis Audet
Slant Six Consulting
Hooksett NH
Original Message:
Sent: 02-28-2024 13:18
From: Rob North
Subject: Chloramine Removal - realistic goals?
Hello Forum! We recently met with a water filtration company, as we are looking to install a system to filter out chloramine. Some of our staff can detect it in our tap water, while others cannot. Our water tested at 0.85 mg/L chloramine.
Our municipality draws its water from a nearby lake (and occasionally a river depending on water levels and demand). I'm curious what levels of chloramine can we reasonable expect to see post filtration, and what our goal should be. Chloramine/chlorine and phenols has not been an issue for us to date in our beers, BUT we are trying to make the best beer possible. It's also more relevant to us as we explore making products which don't require a 60 minute boil and/or go through an extensive fermentation.
The filtration system discussed would, in theory, trickle-fill a large holding tank (an old FV). This holding tank would then supply filtered water to our hot and cold liquor tanks for brewing. CIPs, keg washing, and all non-potable water uses would be drawn from the non-filtered "city water" supply.
I'm eager to hear what people have experienced in this area. Thanks in advance for the help!
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Rob North
Great North Aleworks
Manchester NH
rob@greatnorthaleworks.com
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