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Need 13Amp variac device to 'modulate' a water boiler.
tom66:
You will find that if you set the thermostat to 99C that, most likely, some of the water will still boil because the fluid is not totally uniform and your sensor will be taking just one sample from a large container and the heating element plus convection currents will ensure some of the water has exceeded 100C. Also, of course, environmental pressure variations and any tolerance in your sensor will need to be accounted for.
paulca:
--- Quote from: tom66 on April 19, 2024, 02:04:26 pm ---You will find that if you set the thermostat to 99C that, most likely, some of the water will still boil because the fluid is not totally uniform and your sensor will be taking just one sample from a large container and the heating element plus convection currents will ensure some of the water has exceeded 100C. Also, of course, environmental pressure variations and any tolerance in your sensor will need to be accounted for.
--- End quote ---
Yeah. I was just running this buy some fellow brewers on reddit. Enquiring to the purpose and criticality of a "rolling boil for 1 hour".
Turns out it is more an "ideal" and it's likely the thermostat set to 99.999C or as close as I can get it while still cutting out and not constantly boiling the wort away... it should be fine. I'm not going to ruin the beer, only drop a few percentile on my "ideals".
ealex:
Hello
I've used a dimmer from a "home improvement" store, with 2kw heating elements. I think I had crimp-on ferrules on the cables, and had no issues with overheating. (it was an experiment but lasted way more than expected).
You need to boil it for 2 reasons:
1. Loose some water, so you have a higher sugar % when you start the fermentation - might or might not be desirable - it depends on your recipe and the final volume you can ferment and bottle, but usually diy mashing is not that efficient - you tend to end up with a lot of low concentration worth if you try to wash out all sugars from the mash.
2. Help the bitter compounds dissolve into the beer - might work under the boiling temperature as well - this is also where the 1h boiling time comes from. There are some formulas to estimate the final bitterness from the alpha acid content of the hops you add and the boiling time it sees - the "start of boil" addition will give most of the bitterns but no flavor (or even some unwanted flavors), the last addition will add almost no bitterness and a lot of flavor (for an IPA for example)
I've build my gear from old stainless steel kegs - cut the tops off and re-use the "crown" ( i don't know the proper name ) for the handles that are already there.
Those worked ok with electric and propane heating, but I had to insulate the boiler - a few layers of cardboard where enough to reduce heat loss and easily to replace.
One issue with electric heating: the sugars tend to caramelize and burn on the surface of the heating elements -> you either need very good agitation or heaters that have a high surface area.
One more thing to consider: rapid cooling after the boil - it prevents volatile compound loss and will reduce the time period when the beer can be infected - when it's too hot to pitch the yeast but cold enough for random spores / bacteria to survive.
paulca:
Thanks.
I'm going for "dimmer-less". Working out the volumes I was just going to "wing it". But roughly the following:
Take 25 litres of strike water at 70C, add to mash tun (7 (uk)gal water cooler tub). Adjust if necessary. Cover, leave alone for 1 hour.
Drain the mash into the kettle. I expect maybe only getting 20 litres back with a reasonable drain time.
There are options here, but adding 5 litres of 70C (pre-boiled) water to the mash tun in multiple "rinse/sparge stages" is usually what I do.
So I would be back to 25 litres boil volume, which in a 30litre boiler is as far as I am willing to go.
Technically I need only 19lt out of the fermentor, so ... as you point out... I either need to skimp on the sparge water, the mash volume or reduce the wort through evapouration towards the target "pitching" volume.
To get 19litres comfortably, without too much waste, I probably need a pitching volume of about 22 litres.
3 litres sounds about right for the boil "with" the dimmer.
The boiler is a tea urn. The elements are rings which cover a good area of the base. I still do get some caramel debris, but it's not bad enough to melt the bottom out of a paint strainer bag, (I used to mash in the kettle in a bag)
Instead the plan is to 100% it up to the protein hot break. Then manually alternate the thermostat to nurse it through the same. When it's clear of foam back to 100% towards the rolling boil. In with the hops and the thermostat I will "fiddle" with to get it as close to "pulse boiling" as possible. Where it boils for a 10 seconds starts to get violent, then cuts out and cools below the boil and repeats. (that or I end up fiddling with it constantly).
If I end up with too MUCH evaporation, I can part cover it with a humidity hood (lid). If I end up with less, I just steep it longer or manual supervise a violent boil phase.
I do have a copper coil wort chiller and protofloc which usually results in pretty clear wort at 25*C after an hour.
The frustrating bit, it works exactly like LithiumIon chargers do! The first 50*C goes in minutes. The last 5*C takes over half an hour on it's own! Need colder tap water!
Nice idea with kegs. I'm still not convinced with the need. If I wanted to go propane for pure power that would limit me to boiling in the garage or outdoors.
EDIT: I have a propane cooker hob. But for some reason, using one of those 7kW burners indoors sounds like it would be a bad idea??
themadhippy:
--- Quote ---One more thing to consider: rapid cooling after the boil - it prevents volatile compound loss and will reduce the time period when the beer can be infected -
--- End quote ---
or pour it from the boiler straight into a container that can be sealed air tight and let it cool naturally-aka no chill
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