Is there such a thing as overboiling a wort at too high temperature that it affects taste etc? My boiler has two kettle elements and I normally turn one off when the boil is reached but I dont have a means to control the temperature of this just to maintain a gentle rolling boil..
Overboiling?
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Mark1964
Landlord.
Ours gets a good rolling boil no problems so far 
BigYin
Regular.
someone may correct me, but unless you were to boil the beer in a pressure cooker, you couldn't actually push the temp above about 100c at normal atmospheric pressure :hmm:
You will of course lose more volume to 'boil off' if the boil is vigorous, but you can make that up with boiled water if you feel you've lost too much :thumb:
You will of course lose more volume to 'boil off' if the boil is vigorous, but you can make that up with boiled water if you feel you've lost too much :thumb:
Actually heat loading on a beer is important. Ideally you are looking for around 10-12.5% per hour evaporation rate, in order to achieve a decent hot break and to get decent extraction and isomerisation from the hops. The issue with 3KW elements in a 25L batch is that evaporation rates are often as high as 25-30% this leads to excessive caramelisation, and wort darkening through the Malliard reactions. . . . . which is OK in a malty style as it bigs the malt profile up, but crap in a pale crisp beer.
Too low a heat load (as measured by evaporation) means that your extraction of bitterness from the hops may not bee where you want it.
A lot of commercial beer factories are using external calandria boilers which heat a small volume of the wort rapidly rand return that the the main kettle. The circulation of the wort creates the turbulence that helps keep the extraction rates high, and as the vessels are sealed until the end (when they are vented ) they boil under a slight pressure . . . they are looking at evaporation rates of around 4% (Mainly due to the releasing of pressure at the end of the boil and the massive foaming this creates)
You can use such a thing as a Burst Fire controller (Search United Automations Website) or a Phase Angle Controller to control the power delivered to an element to control the vigour of the boil. The Burst Fire Controller is a better option as it doesn't generate loads of RFI needing an expensive snubber network . . . Both need very large heat sinks however[/url] . . .Mine is attached to a 6mm Aluminium plate
Too low a heat load (as measured by evaporation) means that your extraction of bitterness from the hops may not bee where you want it.
A lot of commercial beer factories are using external calandria boilers which heat a small volume of the wort rapidly rand return that the the main kettle. The circulation of the wort creates the turbulence that helps keep the extraction rates high, and as the vessels are sealed until the end (when they are vented ) they boil under a slight pressure . . . they are looking at evaporation rates of around 4% (Mainly due to the releasing of pressure at the end of the boil and the massive foaming this creates)
You can use such a thing as a Burst Fire controller (Search United Automations Website) or a Phase Angle Controller to control the power delivered to an element to control the vigour of the boil. The Burst Fire Controller is a better option as it doesn't generate loads of RFI needing an expensive snubber network . . . Both need very large heat sinks however[/url] . . .Mine is attached to a 6mm Aluminium plate
BigYin
Regular.
I run one element to maintain a rolling boil, and its controlled by a PID set to 102c - set lower than that and its more of an on-off boil :hmm:
![BREWING THERMOMETER STICKERS ACCURATELY MONITOR FERMENTING BEER & WINE LIQUID TEMPERATURES 5PCS HOME BREW SPIRITS WINE LCD ADHESIVE [US]](https://m.media-amazon.com/images/I/311DDjo2X3L._SL500_.jpg)
All the PID is doing is acting as a thermostat to control the element on / off OK so quite quickly on of but still just on or off . . . what A BFR or PAC does is turn the power down to the element . . . which lowers the heat applied to the wort, thereby maintaining a rolling boil without excessive darkening.
some interesting points raised I think and thanks for the links Aleman.
I made a brew last saturday and my evaporation was literally 'through the roof'! What should have been 25L into the FV ended up as 22L - this was starting from a preboil volume of 33L! :shock: I know it was pretty cold on Saturday but still...
I made a brew last saturday and my evaporation was literally 'through the roof'! What should have been 25L into the FV ended up as 22L - this was starting from a preboil volume of 33L! :shock: I know it was pretty cold on Saturday but still...
One other point to remember, putting a lid on the boiler, even partial, does not reduce the heat loading, although it may reduce the 'evaporation' though condensation and dripping back into the wort.
It is thermal loading that is important, and the only way we have to measure this is via open boiler evaporation rates. Incidentally it has been reported that an evaporation of > 20% develops the melanoidins traditionally associated with decoction mashing, even if it was a single tempt infusion mashed beer, and an evaporation rate of <10% produces a beer with a less malty profile . . .even it it was decoction mashed!
It is thermal loading that is important, and the only way we have to measure this is via open boiler evaporation rates. Incidentally it has been reported that an evaporation of > 20% develops the melanoidins traditionally associated with decoction mashing, even if it was a single tempt infusion mashed beer, and an evaporation rate of <10% produces a beer with a less malty profile . . .even it it was decoction mashed!
Hmm need to keep an eye on this I think. When I built my stainless brewery I also copied an idea from BB regarding a boiler steam hat to vent the steam outside rather than inside the shed. Last week I brewed without that as I was starting to think maybe the condensate from the steam hat was dripping back into the wort and spoiling the taste..
would something as simple as this suffice for controlling the power level to the element?
http://www.dimplex.co.uk/assets/product ... 1_J42a.pdf
http://www.dimplex.co.uk/assets/product ... 1_J42a.pdf
simonranson
Regular.
Would a PID running in manual mode work?
Simon
Simon
BigYin
Regular.
simonranson said:
a PID works by switching the heating element on and off rapidly. It HAS to use relays to actually switch the element.
Once the PID has learnt the heating profile of your setup, it will allow the element to stay constantly on until the temperature is approaching the target temp, and then it will start flicking the element on and off, initially more on than off, moving to more off than on as it gets closer and closer to the target temp. Then it will keep the element off until the temp starts to drop, and it will then turn the element on and off in an effort to maintain the target temperature.
As for other methods of controlling temperature, I understand the BFR or PAC controllers work by turning the power up and down rather than on and off. However if you google 'temperature controller' you generally get PIDs, and if you google PAC temperature you get sleeping bags (amongst other things :lol: ) :wha:
timbim
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I think using a PIR stands to knacker at least the SSR fairly quickly, if not other parts of the system as well. It doesn't stop the wort in direct contact with the element when it's on superheating, which may or may not be significant. A PID is really designed for a very different task from this one, I think I'll plump for the burst fire controller when I finally get round to building a thermopot boiler. Expensive, but correct.
Tim
Tim
simonranson
Regular.
I've just found it in the instructions for my PID that arrived on Monday....
--------
8. Manual mode
Manual mode allows the user to control the output as a percentage of the total
heater power. It is like a stove dial. The output is independent of the
temperature sensor reading. One application example is controlling the
strength of boiling during beer brewing. You can use the manual mode to
control the boiling so that it will not boil over to make a mess. The manual
mode can be switched from PID mode but not from On/off mode. To switch
from the PID to the manual mode, press and hold the key until the
âAT/Mâ indicator turned on (about 5 seconds). In the manual mode, the top
display is for the process temperature. The bottom right is the percentage of
power output. The bottom left display show an âMâ for user to easily identify
the controller is in manual mode. To switch from manual to PID mode,
press and hold 'set' key until the âAT/Mâ indicator turned off. This controller
offers âbumplessâ switch from the PID to manual mode. If the controller
outputs 75% of power at PID mode, the controller will stay at 75% when it is
switched to the manual mode, until it is adjusted manually.
---------------
... I'll give it a go :)
--------
8. Manual mode
Manual mode allows the user to control the output as a percentage of the total
heater power. It is like a stove dial. The output is independent of the
temperature sensor reading. One application example is controlling the
strength of boiling during beer brewing. You can use the manual mode to
control the boiling so that it will not boil over to make a mess. The manual
mode can be switched from PID mode but not from On/off mode. To switch
from the PID to the manual mode, press and hold the key until the
âAT/Mâ indicator turned on (about 5 seconds). In the manual mode, the top
display is for the process temperature. The bottom right is the percentage of
power output. The bottom left display show an âMâ for user to easily identify
the controller is in manual mode. To switch from manual to PID mode,
press and hold 'set' key until the âAT/Mâ indicator turned off. This controller
offers âbumplessâ switch from the PID to manual mode. If the controller
outputs 75% of power at PID mode, the controller will stay at 75% when it is
switched to the manual mode, until it is adjusted manually.
---------------
... I'll give it a go :)
It won't do what you want, it achieves 75% power by switching the element off for 25% of a 'cycle' . . .If a cycle is say 10 seconds long then the element will be off for 2.5 seconds and on for 7.5 Seconds (the cycle is likely to be much shorter than this) . . . making it a digital version of a simmerstatsimonranson said:
simonranson
Regular.
Aleman said:
Thanks for the info. I'll look at getting one of the burst-fire controlelrs you linked to...
Cheers
Simon
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