Boiling water / Cold water ratios

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RichieBeer

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Hi

I've just started my second ever kit brew (St Peters' Golden Ale). Now, I've learnt from reading here, to take the instructions that come with any kit with a pinch of salt. But I thought that mainly referred to the optimistic fermentation times.

Anyway, the instruction say to pour the extract into the FV and add 3.5 litres (6 pints) of boiling water and to top up to the required amount (20.5 litres in this case) with cold water. However after doing that the temperature of the wort was almost 30°C - which I understand is far too warm to pitch the yeast and I had to leave it overnight before it was cool enough to add the yeast. (although I notice the instructions don't say anything about the temperature it should be when you add yeast)

The same thing happened when I did my first brew too (Wherry). I appreciate "cold" water can have quite a range, but mine comes out of the cold tap and other than adding ice cubes (a big no-no??) to bring the temperature down I'm not sure what the options are.

So next time, is it simply a case of starting with less boiling water? Is there a reason why they specify a particular amount of boiling water? Does anyone know the magic ratio of boiling water to cold tap water to get a suitable temperature to pitch yeast.

thank you...
 
It can be highly dependant on your incoming water temp. Rest the tins in hot water before opening to soften the extract then rinse out with boiled water...mind your hands though!
The hot water is to make mixing it all together easier...get your spoon and thrash it up. There's no ideal ratios just whatever works.
 
It can be highly dependant on your incoming water temp. Rest the tins in hot water before opening to soften the extract then rinse out with boiled water...mind your hands though!
The hot water is to make mixing it all together easier...get your spoon and thrash it up.

I did all that, but I reckon the cold water would have to be at least fridge cold (just a few degrees C) to finish with a cool enough wort to pitch.
 
I've never actually tried one out but their are online calculators for this kind of thing

https://rechneronline.de/chemie-rechner/mix-temperatures.php

Interesting, thanks for that, MyQul.

That calculator would suggest I needed to add cold water at about 4-5°C (assuming the "boiling" water would have fallen a few degrees by the time I'm ready to add the cold). A fair bit colder than it would come out of the average kitchen tap I would guess.
 
Interesting, thanks for that, MyQul.

That calculator would suggest I needed to add cold water at about 4-5°C (assuming the "boiling" water would have fallen a few degrees by the time I'm ready to add the cold). A fair bit colder than it would come out of the average kitchen tap I would guess.

Like I say, I've never actually used one of these calcualtors 'in anger' but their are a number of them. Just google 'liquid mix temperature calculator'. See if you get the same results on more than one
 
According to graph on this link, http://www.silverspray.co.uk/2012/12/13/cold-water-tap-temperature/ cold water tap temperature could be around 10° at the moment. Obviously it's affected by seasonal temperature variations.

DHW-SeasonalEnergyReq.jpg


Although according to this story http://www.bbc.co.uk/news/uk-england-12073944, Thames Water say mains water should average about 7.5 degrees.
 
Go with one kettle full mate. Works well for me. Boil another half kettle and check temp once you're getting towards the volume and use the second half if necessary.
I usually empty the can as much as possible then fill the can with the kettle and stir to get everything out of can. I also find this saves having to warm the can as well. Just be careful lifting them with the hot water in obviously.
 
I usually do the following with my kits:

Add 20/22 litres of cold tapwater to a spare fv. I do this by using a jug and emptying it from above waist height to help aerate the water and drive off any chlorine. I then add half a crushed campden tablet and let it stand for half an hour.

I add a couple of litres of this water to the fv I'm going to be using. Then add the malt extract from the tins (which have been standing in a pan of warm/hot water to soften the extract). Stir like crazy.

Fill the tins with water boiled in a kettle and empty this into the fv to get the last bits of the extract out.

Then top up the fv to the required volume with the treated cold water. Remember to thrash the water with a sterilized spoon after every 3 or 4 litres or so to ensure that the extract is mixed/the wort is aerated/and the hot and cold water mix.

This usually gets the temperature down to 25C or so. I mixed a kit up yesterday evening and the resulting temperature was 22C but in warmer weather, I would expect it to be higher as the cold water temp is higher. Using this method, I rarely end up with a temp above 30C.
 
I fully believe that back in the early days this was why I had one or two non-starters as I used to use upwards of two kettles full of water to rinse out the cans / dissolve the extract, sugar etc. and I never checked the temperature.

I now check the temperature before pitching and I've found that anymore than around a kettle full of boiling water in a 5 gallon kit will push the final temperature over 20°C. I'm happy with lobbing the yeast in up to about 25°C as all my brews are now fermented in a brew fridge so it will get chilled down fairly rapidly but I do try to keep it as near to 20°C as I can.
 
Thanks for the comments.

I think in future I'll just go with the one kettle full (think mine is about 1.5 litres) and top up with cold from there and add more from the kettle towards the top if necessary.

Think mine was down to about 23° when I finally popped the yeast in so hopefully it'll be OK.
 
Wot I do....
Use just enough off-the-boil water to dissolve the LME into solution.
Then top up with cold water to about 2-3 litres of the final intended brew volume.
Make sure the wort is mixed properly.
Then take the wort temperature.
Unless it is very hot weather (and the mains water coming out of the tap is warmer than normal; this summer it hit 19*C) it should be somewhere around 20*C.
Then top up to final volume with boiling water and mains water as required to adjust to the desired temperature, mixing and taking the temperature as I go. Even at this stage a litle hot water can raise the temperature quite alot.
 
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