Pour Mash Efficiency

[Mike Neilson]

Heres my thought, I used to average around 80-85 efficiency every brew, But latley I have been only able to achieve 70-75%. One thing I have noticed is the the local Tap water here has a distinct Chlorine smell to it, my question is what effect does the chlorine have on the mash enzymes? I am also noticing that my mash is taking longer to convert, like last week my 65 Deg Mash took 2 1/4 Hours!! and this weeks 67 Degree mash to 85 mins!! Same mash used to take 40!!
I have a filter on my house supply but im thinking it may needed to be changed!!

[JoKing]

Are you using the same malt?

[Tony]

Yeah, my initial thoughts also, was your malt? How old is the malts? How long between when it was crushed and when you mashed it? Once it is crushed, it needs to be used ASAP, otherwise it will deteriorate, over time.

[Mike Neilson]

Same Malt I have achieved 85%, but thats before the water became 15deg out of tap? Im only taking a guess but with warmer temps surly their chlorine rates must increase also?

[Mike Neilson]

Yeah scales all good, Malt arrived into Chch from Germany end of August. Malt is crushed normaly while strike water is being bought up to temp.

[Reviled]

Changed the batteries on your scales recently?

[denimglen]

Yeah, sure your scales and/or hydrometer are still accurate?

How's your water mineral wise? Some calcium in the mash doesn't go a miss, helps the enzymes in a few ways.

[Michael]

All of you know a lot more about brewing than me. However, I do have a thought for you to consider.

The boiling point of Chlorine is -34.6 º C. You are likely heating up your water well beyond that. As such, if you have the water heated close to mashing temps, it would seem that the chlorine would have been boiled away. I mention this since I used to boil water to get the chlorine out before cooling it down and pouring into a fish tank. (the chlorine will kill them, especially some of the exotics I had.)

This does not mean that there cannot be a any residue, but it would seem that the more likely cause of issues would be other minerals in the water. For long-term brewing, you may want to consider a filter on your water supply, and then tune the water to the levels you need.

[denimglen]

Chlorine in water is a little more stable than chlorine by itself, otherwise there would be none left in the water by time it left your tap.

Also it's usually chloramines used to treat water now which is much more stable in solution, and boiling won't get rid of it, but metabisulfite will.

[Steve Baker]

Chlorine levels of Wellington water seems to oscillate wildly. I've heard that it will evaporate out of standing water over 24 hours, so you could try filling your HLT the day before and leaving it with the lid off.

No idea what effect it has on the mash tho.

[denimglen]

I've never heard of chlorine effecting the mash - just creating things like chlorophenols during fermentation.

Im only taking a guess but with warmer temps surly their chlorine rates must increase also?

I noticed a stronger chlorine smell in the water over winter in AK - dunno whether they add more or the warmer temps in summer make it flash out a little faster.

Have you checked you mill gap? Might have adjusted itself out a little or something?

Thermometer still reading true?

I'd say add a couple of grams of CaCl or CASO4 next mash and see if that helps, can't hurt either, I assume your guys water is relatively soft?

[Mike Neilson]

Yeah Everything is reading true and correct. my mash water is always at 70 - 80ppm Ca, My mill is set just below stuck mash.

[Reviled]

Youve got a monster mill eh? What setting do you have it at?