Induction cooktops, temperature control questions

[Joerg]

Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction cooktops
can be had with 1.8kW but realistically more like 1.5kW on a 15A
circuit. That's more and supposedly the induction method is more efficient.

However ... for reasons that I'll never understand the temperature can
only be set in 40F increments and very occasionally there are units with
10F steps. Way too coarse for brewing. Even for sous-vide chefs that
isn't good enough. I am talking about the usual $50 price range, not $1k
restaurant grade. The thermostats on my $12 Walmart cooktops are nicely
analog-controlled so I can set them exactly where needed.

I assume the firmware in the internal uC can't be touched so that leaves
a hack. If it was an NTC or PTC that reads back the temperature I could
hang a potentiometer in series to obtain a vernier control and tape a
cheat sheet "real temperature versus indicated" on each cooktop.

Has anyone done that? Did it work well? If not, can these cooktops be
controlled "bang-bang" via an external PID loop?

Other question: My brew kettle is aluminum so it would need some sort of
steel plate thrown into the bottom. Considerung the thickness of the
aluminum bottom this plate would ride 1/8" to 1/4" above the cooktop
surface. How much power into the liquid would I lose?

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 2019-05-23 09:04, John Larkin wrote:

On Thu, 23 May 2019 08:29:49 -0700, Joerg <news@analogconsultants.com
wrote:

Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction cooktops
can be had with 1.8kW but realistically more like 1.5kW on a 15A
circuit. That's more and supposedly the induction method is more efficient.

Inductive heating must be less efficient than resistive. Resistive is
best if you can make a good thermal connection to your kettle.

From what I heard and read so far inductiove is more efficient. Power
loss in the bridge FETs and coil is so low that a small fan suffices but
there is almost no more transfer loss.

How about an aluminum plate, some big resistors bolted to the bottom,
a thin gap-pad on top? That would hardly lose any heat, except from
the surface of the kettle itself. Wrap it in a cozy.

That would make kettle cleaning a bear.

Or dunk a big resistor into the mash.

Some people use immersion heaters. However, those get in the way because
one must occasionally stir. It also would require to crack the lid too
much or drill the kettle and mount in permanently. The latter make
cleaning tough and stirring nearly impossible. Striing is important when
working with malt sirup, dry malt extract or Belgian candi sugar. The
latter is indispensable for serious Belgian Tripel or Quad, my favorite
beer.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Thu, 23 May 2019 08:29:49 -0700, Joerg <news@analogconsultants.com>
wrote:

Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction cooktops
can be had with 1.8kW but realistically more like 1.5kW on a 15A
circuit. That's more and supposedly the induction method is more efficient.

Inductive heating must be less efficient than resistive. Resistive is
best if you can make a good thermal connection to your kettle.

How about an aluminum plate, some big resistors bolted to the bottom,
a thin gap-pad on top? That would hardly lose any heat, except from
the surface of the kettle itself. Wrap it in a cozy.

Or dunk a big resistor into the mash.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Joerg]

On 2019-05-23 10:37, bitrex wrote:

On 5/23/19 11:29 AM, Joerg wrote:
Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction
cooktops can be had with 1.8kW but realistically more like 1.5kW on a
15A circuit. That's more and supposedly the induction method is more
efficient.

However ... for reasons that I'll never understand the temperature can
only be set in 40F increments and very occasionally there are units
with 10F steps. Way too coarse for brewing. Even for sous-vide chefs
that isn't good enough.

I thought sous vide had to be even tighter than 10F

Yes, that is why I think even the 10F setting isn't good enough for
sous-vide. Beats me why they don't improve that. Here is how this can be
achieved at a $0.00 BOM cost increase:

The barbecue thermometer I use to monitor the brew kettle via radio link
also has only a few temp settings. Rare, medium, done, et cetera.
However, the engineers were smart and when you hold the temp set button
for a coupe of seconds the controller goes into a custom setting mode.
The display starts to blink and now you can set temps to within 1F.
Press set once more, blinking stops, done.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Jan Panteltje]

On a sunny day (Thu, 23 May 2019 10:12:01 -0700) it happened Joerg
<news@analogconsultants.com> wrote in <gko2ioFlojcU1@mid.individual.net>:

On 2019-05-23 09:47, Jan Panteltje wrote:
On a sunny day (Thu, 23 May 2019 08:29:49 -0700) it happened Joerg
news@analogconsultants.com> wrote in <gknsj3Fkf5cU1@mid.individual.net>:

Thinking about induction cooktops for beer brewing

I have one, bought it some years ago,
and everytime I switch that thing on it sort of gives me a headache.
So it went into the attic within a day.
My theory is that there are magnetic sensitive particles in the brain that get shaken by the stray field.
Why my other lower power RF (100 kHz?) ebay one (the bad one is 50 Hz)) does not bother me I do not know.
Maybe exitation is then too fast.

So be warned.


AFAIK induction cooktops work in the 20-30kHz range. The field is strong
but supposedly negligible past 10cm distance. Maybe you are really
sensitive to it.

Or did you have too much Beerenburger before the headache set in?

No, will be bit more clear (my fault),
with 50 Hz I ment 50 Hz mains, of course ?? I opened mine up to see what
caused the problem, and I did not come across a lot of mains filter caps,
just a bridge, some switcher, big coils, so the RF (well it is still LF actually)
is possibly strongly modulated by the mains frequency 100 Hz from the bridge rectifier.

My ebay induction heater runs on 12V DC, this one:
https://www.ebay.com/itm/361287263867

The bad one is this one:
König HA-INDUC-11N design inductiekookplaat 2000 W
was only 55 Euro..

For the ebay one I made a nice cooking coil:
http://panteltje.com/pub/inductive_heating_current_spiral_coil_baco_IMG_5211.JPG

There is a youtube video of me frying an egg with that:
https://www.youtube.com/watch?v=iyTnr25aTxc

You can fry an egg with one small 3 cell 2200mAh 11.1 V RC plane Lipo!
Now that is efficient!

Been a while since I had berenburger really...
We have European elections today here, now that is also interesting...

 

[Joerg]

On 2019-05-23 09:47, Jan Panteltje wrote:

On a sunny day (Thu, 23 May 2019 08:29:49 -0700) it happened Joerg
news@analogconsultants.com> wrote in <gknsj3Fkf5cU1@mid.individual.net>:

Thinking about induction cooktops for beer brewing

I have one, bought it some years ago,
and everytime I switch that thing on it sort of gives me a headache.
So it went into the attic within a day.
My theory is that there are magnetic sensitve particles in the brain that get shaken by the stray field.
Why my other lower power RF (100 kHz?) ebay one (the bad one is 50 Hz)) does not bother me I do not know.
Maybe exitation is then too fast.

So be warned.

AFAIK induction cooktops work in the 20-30kHz range. The field is strong
but supposedly negligible past 10cm distance. Maybe you are really
sensitive to it.

Or did you have too much Beerenburger before the headache set in?

--
Regards, Joerg

http://www.analogconsultants.com/

 

[bitrex]

On 5/23/19 11:29 AM, Joerg wrote:

Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction cooktops
can be had with 1.8kW but realistically more like 1.5kW on a 15A
circuit. That's more and supposedly the induction method is more efficient.

However ... for reasons that I'll never understand the temperature can
only be set in 40F increments and very occasionally there are units with
10F steps. Way too coarse for brewing. Even for sous-vide chefs that
isn't good enough.

I thought sous vide had to be even tighter than 10F

 

[Jan Panteltje]

On a sunny day (Thu, 23 May 2019 08:29:49 -0700) it happened Joerg
<news@analogconsultants.com> wrote in <gknsj3Fkf5cU1@mid.individual.net>:

>Thinking about induction cooktops for beer brewing

I have one, bought it some years ago,
and everytime I switch that thing on it sort of gives me a headache.
So it went into the attic within a day.
My theory is that there are magnetic sensitve particles in the brain that get shaken by the stray field.
Why my other lower power RF (100 kHz?) ebay one (the bad one is 50 Hz)) does not bother me I do not know.
Maybe exitation is then too fast.

So be warned.

 

[whit3rd]

On Thursday, May 23, 2019 at 9:48:01 AM UTC-7, Jan Panteltje wrote:

On a sunny day (Thu, 23 May 2019 08:29:49 -0700) it happened Joerg
news@analogconsultants.com> wrote in <gknsj3Fkf5cU1@mid.individual.net>:

Thinking about induction cooktops for beer brewing

I have one, bought it some years ago,
and everytime I switch that thing on it sort of gives me a headache.
So it went into the attic within a day.
My theory is that there are magnetic sensitve particles in the brain ...

Or, maybe just an allergy to something that outgasses (in which case,
the year in the attic will cure it), or (scary thought) ozone from
a high voltage section.

 

[Joerg]

On 2019-05-23 11:02, Lasse Langwadt Christensen wrote:

torsdag den 23. maj 2019 kl. 17.29.44 UTC+2 skrev Joerg:
Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction cooktops
can be had with 1.8kW but realistically more like 1.5kW on a 15A
circuit. That's more and supposedly the induction method is more efficient.

However ... for reasons that I'll never understand the temperature can
only be set in 40F increments and very occasionally there are units with
10F steps. Way too coarse for brewing. Even for sous-vide chefs that
isn't good enough. I am talking about the usual $50 price range, not $1k
restaurant grade. The thermostats on my $12 Walmart cooktops are nicely
analog-controlled so I can set them exactly where needed.

I assume the firmware in the internal uC can't be touched so that leaves
a hack. If it was an NTC or PTC that reads back the temperature I could
hang a potentiometer in series to obtain a vernier control and tape a
cheat sheet "real temperature versus indicated" on each cooktop.

Has anyone done that? Did it work well? If not, can these cooktops be
controlled "bang-bang" via an external PID loop?

Other question: My brew kettle is aluminum so it would need some sort of
steel plate thrown into the bottom. Considerung the thickness of the
aluminum bottom this plate would ride 1/8" to 1/4" above the cooktop
surface. How much power into the liquid would I lose?


get an all in one wonder
https://www.hjemmebryggeren.dk/brygudstyr/bryganlaeg/2403-brewster-ng-25-liters-bryganlaeg

Aside from the cost that would not help much because it's 2500W, only
25% more than what I have now.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 2019-05-23 10:42, Jan Panteltje wrote:

On a sunny day (Thu, 23 May 2019 10:12:01 -0700) it happened Joerg
news@analogconsultants.com> wrote in <gko2ioFlojcU1@mid.individual.net>:

On 2019-05-23 09:47, Jan Panteltje wrote:
On a sunny day (Thu, 23 May 2019 08:29:49 -0700) it happened Joerg
news@analogconsultants.com> wrote in <gknsj3Fkf5cU1@mid.individual.net>:

Thinking about induction cooktops for beer brewing

I have one, bought it some years ago,
and everytime I switch that thing on it sort of gives me a headache.
So it went into the attic within a day.
My theory is that there are magnetic sensitive particles in the brain that get shaken by the stray field.
Why my other lower power RF (100 kHz?) ebay one (the bad one is 50 Hz)) does not bother me I do not know.
Maybe exitation is then too fast.

So be warned.


AFAIK induction cooktops work in the 20-30kHz range. The field is strong
but supposedly negligible past 10cm distance. Maybe you are really
sensitive to it.

Or did you have too much Beerenburger before the headache set in?

No, will be bit more clear (my fault),
with 50 Hz I ment 50 Hz mains, of course ?? I opened mine up to see what
caused the problem, and I did not come across a lot of mains filter caps,
just a bridge, some switcher, big coils, so the RF (well it is still LF actually)
is possibly strongly modulated by the mains frequency 100 Hz from the bridge rectifier.

They have to operate that way. Not just because the electrolytic would
be expensive and failure-prone but mainly because they would otherwise
blow the power factor regulations. Or they would need an extra PFC stage
which really adds cost.

My ebay induction heater runs on 12V DC, this one:
https://www.ebay.com/itm/361287263867

Nice!

The bad one is this one:
König HA-INDUC-11N design inductiekookplaat 2000 W
was only 55 Euro..

For the ebay one I made a nice cooking coil:
http://panteltje.com/pub/inductive_heating_current_spiral_coil_baco_IMG_5211.JPG

There is a youtube video of me frying an egg with that:
https://www.youtube.com/watch?v=iyTnr25aTxc

You can fry an egg with one small 3 cell 2200mAh 11.1 V RC plane Lipo!
Now that is efficient!

Took a long time though but maybe because you held the pan at 1cm or
more distance. Be careful taxing the batteries so much, it takes away
some of their useful life. It may be better to use an automotive battery.

Been a while since I had berenburger really...
We have European elections today here, now that is also interesting...

Maybe you need that Berenburger when the results come in

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Lasse Langwadt Christense]

torsdag den 23. maj 2019 kl. 17.29.44 UTC+2 skrev Joerg:

Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction cooktops
can be had with 1.8kW but realistically more like 1.5kW on a 15A
circuit. That's more and supposedly the induction method is more efficient.

However ... for reasons that I'll never understand the temperature can
only be set in 40F increments and very occasionally there are units with
10F steps. Way too coarse for brewing. Even for sous-vide chefs that
isn't good enough. I am talking about the usual $50 price range, not $1k
restaurant grade. The thermostats on my $12 Walmart cooktops are nicely
analog-controlled so I can set them exactly where needed.

I assume the firmware in the internal uC can't be touched so that leaves
a hack. If it was an NTC or PTC that reads back the temperature I could
hang a potentiometer in series to obtain a vernier control and tape a
cheat sheet "real temperature versus indicated" on each cooktop.

Has anyone done that? Did it work well? If not, can these cooktops be
controlled "bang-bang" via an external PID loop?

Other question: My brew kettle is aluminum so it would need some sort of
steel plate thrown into the bottom. Considerung the thickness of the
aluminum bottom this plate would ride 1/8" to 1/4" above the cooktop
surface. How much power into the liquid would I lose?

get an all in one wonder
https://www.hjemmebryggeren.dk/brygudstyr/bryganlaeg/2403-brewster-ng-25-liters-bryganlaeg

 

[Gerhard Hoffmann]

Am 23.05.19 um 21:08 schrieb Gerhard Hoffmann:

My induction stove runs on 2 phases Ă  240V. It can divert the energy of
the 2 back burners to the front, so there are 7 KW on the 2 front plates
together. It is better not to go far away when using that; a pot may
behave like a volcano after a short time ;-)

While normal steel pans don't work on induction, I was delighted that
Grandma's old cast iron pans (like for a goose) work nicely.

Maybe the aluminium pot even shields the lossy iron from the induction
coils, so it may be better to put the iron plate below the alu pot.

Making beer seems to be a fundamental problem of man. Hammurabi's
stone stele talks about it (punishment for those who don't do it right)
and the nordic gods once went to war against the giants over a
huge brewing kettle. Seems more acceptable and understandable
than over non-existing weapons of mass destruction.

9pm, good time for a beer.

cheers,
Gerhard

Maybe a large "Tauchsieder" would do, or two of them.
Temperature control would be not much of a problem for JĂśrg.

Ah. WordReference calls it immersion heater.

 

[Gerhard Hoffmann]

Am 23.05.19 um 20:27 schrieb Joerg:

On 2019-05-23 11:02, Lasse Langwadt Christensen wrote:
torsdag den 23. maj 2019 kl. 17.29.44 UTC+2 skrev Joerg:
Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction cooktops
can be had with 1.8kW but realistically more like 1.5kW on a 15A
circuit. That's more and supposedly the induction method is more
efficient.

However ... for reasons that I'll never understand the temperature can
only be set in 40F increments and very occasionally there are units with
10F steps. Way too coarse for brewing. Even for sous-vide chefs that
isn't good enough. I am talking about the usual $50 price range, not $1k
restaurant grade. The thermostats on my $12 Walmart cooktops are nicely
analog-controlled so I can set them exactly where needed.

I assume the firmware in the internal uC can't be touched so that leaves
a hack. If it was an NTC or PTC that reads back the temperature I could
hang a potentiometer in series to obtain a vernier control and tape a
cheat sheet "real temperature versus indicated" on each cooktop.

Has anyone done that? Did it work well? If not, can these cooktops be
controlled "bang-bang" via an external PID loop?

Other question: My brew kettle is aluminum so it would need some sort of
steel plate thrown into the bottom. Considerung the thickness of the
aluminum bottom this plate would ride 1/8" to 1/4" above the cooktop
surface. How much power into the liquid would I lose?


get an all in one wonder
https://www.hjemmebryggeren.dk/brygudstyr/bryganlaeg/2403-brewster-ng-25-liters-bryganlaeg



Aside from the cost that would not help much because it's 2500W, only
25% more than what I have now.

My induction stove runs on 2 phases Ă  240V. It can divert the energy of
the 2 back burners to the front, so there are 7 KW on the 2 front plates
together. It is better not to go far away when using that; a pot may
behave like a volcano after a short time ;-)

While normal steel pans don't work on induction, I was delighted that
Grandma's old cast iron pans (like for a goose) work nicely.

Maybe the aluminium pot even shields the lossy iron from the induction
coils, so it may be better to put the iron plate below the alu pot.

Making beer seems to be a fundamental problem of man. Hammurabi's
stone stele talks about it (punishment for those who don't do it right)
and the nordic gods once went to war against the giants over a
huge brewing kettle. Seems more acceptable and understandable
than over non-existing weapons of mass destruction.

9pm, good time for a beer.

cheers,
Gerhard

 

[John Larkin]

On Thu, 23 May 2019 09:19:35 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-05-23 09:04, John Larkin wrote:
On Thu, 23 May 2019 08:29:49 -0700, Joerg <news@analogconsultants.com
wrote:

Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction cooktops
can be had with 1.8kW but realistically more like 1.5kW on a 15A
circuit. That's more and supposedly the induction method is more efficient.

Inductive heating must be less efficient than resistive. Resistive is
best if you can make a good thermal connection to your kettle.


From what I heard and read so far inductiove is more efficient. Power
loss in the bridge FETs and coil is so low that a small fan suffices but
there is almost no more transfer loss.

A resistor is 100% efficient. The only better thing would be a heat
pump.

How about an aluminum plate, some big resistors bolted to the bottom,
a thin gap-pad on top? That would hardly lose any heat, except from
the surface of the kettle itself. Wrap it in a cozy.


That would make kettle cleaning a bear.

The cute knitted cozy slips right off. The gap-pad stuff stays stuck
to the heater plate; the kettle just sits on it for good heat
transfer.

Or dunk a big resistor into the mash.


Some people use immersion heaters. However, those get in the way because
one must occasionally stir. It also would require to crack the lid too
much or drill the kettle and mount in permanently. The latter make
cleaning tough and stirring nearly impossible. Striing is important when
working with malt sirup, dry malt extract or Belgian candi sugar. The
latter is indispensable for serious Belgian Tripel or Quad, my favorite
beer.

BevMo sells beer.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Joerg]

On 2019-05-23 11:45, John Larkin wrote:

On Thu, 23 May 2019 09:19:35 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-05-23 09:04, John Larkin wrote:
On Thu, 23 May 2019 08:29:49 -0700, Joerg <news@analogconsultants.com
wrote:

Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction cooktops
can be had with 1.8kW but realistically more like 1.5kW on a 15A
circuit. That's more and supposedly the induction method is more efficient.

Inductive heating must be less efficient than resistive. Resistive is
best if you can make a good thermal connection to your kettle.


From what I heard and read so far inductiove is more efficient. Power
loss in the bridge FETs and coil is so low that a small fan suffices but
there is almost no more transfer loss.

A resistor is 100% efficient. The only better thing would be a heat
pump.

So is the electric coil cooktop but getting the heat into the wort is
the trick.

How about an aluminum plate, some big resistors bolted to the bottom,
a thin gap-pad on top? That would hardly lose any heat, except from
the surface of the kettle itself. Wrap it in a cozy.


That would make kettle cleaning a bear.

The cute knitted cozy slips right off. The gap-pad stuff stays stuck
to the heater plate; the kettle just sits on it for good heat
transfer.

The gap pad would probably help but I don't see how that's going to
perform much differently than ye olde Walmart cooktop.

Or dunk a big resistor into the mash.


Some people use immersion heaters. However, those get in the way because
one must occasionally stir. It also would require to crack the lid too
much or drill the kettle and mount in permanently. The latter make
cleaning tough and stirring nearly impossible. Striing is important when
working with malt sirup, dry malt extract or Belgian candi sugar. The
latter is indispensable for serious Belgian Tripel or Quad, my favorite
beer.

BevMo sells beer.

Yes, they sell some good stuff. It still can't hold a candle to
homebrew. Once you got used to that you don't want any other. The only
beer that remains acceptable to me is fresh from tap but only if brewed
right there and very fresh. Plus commercial beer that is
bottle-fermented but except for some Hefeweizen brands and very few
Belgians commercial breweries stopped doing that for cost reasons.
Bottle fermentation is one of the key upside of homebrew.

When some of us were close to receiving our engineering degrees and
found out that our ivy league place didn't even have as much as a tassel
hat ceremony we rented a whole bar for a night. Brew was not included so
we brewed like crazy and then bought a stack of Grolsch crates because
the place would be packed. So our beer wouldn't suffice. Grolsch is nice
beer but everyone wanted our beer and when it was all gone they were moping.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Jan Panteltje]

On a sunny day (Thu, 23 May 2019 11:36:49 -0700 (PDT)) it happened whit3rd
<whit3rd@gmail.com> wrote in
<8bc39ba8-71d4-4b15-aa0f-9189228f8552@googlegroups.com>:

On Thursday, May 23, 2019 at 9:48:01 AM UTC-7, Jan Panteltje wrote:
On a sunny day (Thu, 23 May 2019 08:29:49 -0700) it happened Joerg
news@analogconsultants.com> wrote in <gknsj3Fkf5cU1@mid.individual.net>:

Thinking about induction cooktops for beer brewing

I have one, bought it some years ago,
and everytime I switch that thing on it sort of gives me a headache.
So it went into the attic within a day.
My theory is that there are magnetic sensitve particles in the brain ...

Or, maybe just an allergy to something that outgasses (in which case,
the year in the attic will cure it), or (scary thought) ozone from
a high voltage section.

It is not like that,
it is immediate, some buzzing in your head, and gone when you switch it off.
Almost like standing next to a leaking microwave oven ..
Maybe their circuit creates harmonics into the infinite,
I sure do not like their circuit,
and the ceramic top plate does not shield against anything.

 

[Joerg]

On 2019-05-23 12:19, Gerhard Hoffmann wrote:

Am 23.05.19 um 21:08 schrieb Gerhard Hoffmann:


My induction stove runs on 2 phases Ă  240V. It can divert the energy of
the 2 back burners to the front, so there are 7 KW on the 2 front plates
together. It is better not to go far away when using that; a pot may
behave like a volcano after a short time ;-)

That's like American power levels. I believe the large front burners of
our range are 3.5kW each. There are seven burners but the ones in back
have less maximum power:

http://analogconsultants.com/ng/images/Kitchen2.jpg

While normal steel pans don't work on induction, I was delighted that
Grandma's old cast iron pans (like for a goose) work nicely.

Maybe the aluminium pot even shields the lossy iron from the induction
coils, so it may be better to put the iron plate below the alu pot.

That's what most people do but it nixes the induction advantages. You
essentially turn it into a regular electric hotplate, minus the losses
in the electronics and stuff. Makes no sense.

Making beer seems to be a fundamental problem of man. Hammurabi's
stone stele talks about it (punishment for those who don't do it right)
and the nordic gods once went to war against the giants over a
huge brewing kettle. Seems more acceptable and understandable
than over non-existing weapons of mass destruction.

Don't nobody touch my brew kettle!

9pm, good time for a beer.

That's when I'll have a Belgian Quadrupel. Homebrew, of course. And
maybe a Barley Wine before that.

cheers,
Gerhard


Maybe a large "Tauchsieder" would do, or two of them.
Temperature control would be not much of a problem for JĂśrg.

Ah. WordReference calls it immersion heater.

That is what some brewers use. I can get such heaters up to 5500W but
it's messy.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Thu, 23 May 2019 13:28:38 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-05-23 11:45, John Larkin wrote:
On Thu, 23 May 2019 09:19:35 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-05-23 09:04, John Larkin wrote:
On Thu, 23 May 2019 08:29:49 -0700, Joerg <news@analogconsultants.com
wrote:

Thinking about induction cooktops for beer brewing because the two 1kW
burners that my brew kettle straddles result in a whopping 2h+ total
just to heat up stuff. On Belgian beers more like 3h. Induction cooktops
can be had with 1.8kW but realistically more like 1.5kW on a 15A
circuit. That's more and supposedly the induction method is more efficient.

Inductive heating must be less efficient than resistive. Resistive is
best if you can make a good thermal connection to your kettle.


From what I heard and read so far inductiove is more efficient. Power
loss in the bridge FETs and coil is so low that a small fan suffices but
there is almost no more transfer loss.

A resistor is 100% efficient. The only better thing would be a heat
pump.


So is the electric coil cooktop but getting the heat into the wort is
the trick.


How about an aluminum plate, some big resistors bolted to the bottom,
a thin gap-pad on top? That would hardly lose any heat, except from
the surface of the kettle itself. Wrap it in a cozy.


That would make kettle cleaning a bear.

The cute knitted cozy slips right off. The gap-pad stuff stays stuck
to the heater plate; the kettle just sits on it for good heat
transfer.


The gap pad would probably help but I don't see how that's going to
perform much differently than ye olde Walmart cooktop.


Or dunk a big resistor into the mash.


Some people use immersion heaters. However, those get in the way because
one must occasionally stir. It also would require to crack the lid too
much or drill the kettle and mount in permanently. The latter make
cleaning tough and stirring nearly impossible. Striing is important when
working with malt sirup, dry malt extract or Belgian candi sugar. The
latter is indispensable for serious Belgian Tripel or Quad, my favorite
beer.

BevMo sells beer.


Yes, they sell some good stuff. It still can't hold a candle to
homebrew. Once you got used to that you don't want any other. The only
beer that remains acceptable to me is fresh from tap but only if brewed
right there and very fresh. Plus commercial beer that is
bottle-fermented but except for some Hefeweizen brands and very few
Belgians commercial breweries stopped doing that for cost reasons.
Bottle fermentation is one of the key upside of homebrew.

When some of us were close to receiving our engineering degrees and
found out that our ivy league place didn't even have as much as a tassel
hat ceremony we rented a whole bar for a night. Brew was not included so
we brewed like crazy and then bought a stack of Grolsch crates because
the place would be packed. So our beer wouldn't suffice. Grolsch is nice
beer but everyone wanted our beer and when it was all gone they were moping.

I forged a letter to get out of attending my college graduation.
Imagine standing in a black robe for a few hours in the sunshine in
New Orleans in June, listening to fatheads drone.

The Brat's graduations, at Cornell and UC Berkeley, were pretty neat,
with tolerable temperatures.

Grolsch has a nice bottle but it's otherwise bland. Lately we like
Guinness Blonde, Purple Haze, Widmer, and Harp. Mo likes Fat Tire but
I think it tastes funny.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Joerg]

On 2019-05-23 14:27, John Larkin wrote:

On Thu, 23 May 2019 13:28:38 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-05-23 11:45, John Larkin wrote:

[...]

BevMo sells beer.


Yes, they sell some good stuff. It still can't hold a candle to
homebrew. Once you got used to that you don't want any other. The only
beer that remains acceptable to me is fresh from tap but only if brewed
right there and very fresh. Plus commercial beer that is
bottle-fermented but except for some Hefeweizen brands and very few
Belgians commercial breweries stopped doing that for cost reasons.
Bottle fermentation is one of the key upside of homebrew.

When some of us were close to receiving our engineering degrees and
found out that our ivy league place didn't even have as much as a tassel
hat ceremony we rented a whole bar for a night. Brew was not included so
we brewed like crazy and then bought a stack of Grolsch crates because
the place would be packed. So our beer wouldn't suffice. Grolsch is nice
beer but everyone wanted our beer and when it was all gone they were moping.

I forged a letter to get out of attending my college graduation.
Imagine standing in a black robe for a few hours in the sunshine in
New Orleans in June, listening to fatheads drone.

That is very different at my school (RWTH Aachen University, Germany).
Now that they started having the tassel hat parties they've got food
stands and beer! See 0:34min here:

https://www.youtube.com/watch?v=nydAvyUaVu0

The Brat's graduations, at Cornell and UC Berkeley, were pretty neat,
with tolerable temperatures.

Grolsch has a nice bottle but it's otherwise bland. Lately we like
Guinness Blonde, Purple Haze, Widmer, and Harp. Mo likes Fat Tire but
I think it tastes funny.

This isn't the old Grolsch anymore. The company was bought up twice and
IMHO that hasn't been good for the taste.

--
Regards, Joerg

http://www.analogconsultants.com/