| |
Main
Date: 08 Dec 2006 06:02:03
From: Steve/Aus
Subject: Temp difference in Freezer
|
I thought my chest type freezer with electronic external controller was
running warmer than it should. I had it set at 0°C off and 2°C on with the
temp probe at the bottom of the freezer. This morning I lifted the probe up
to about the halfway mark and the temperature was a full 5°C warmer!
I normally keep it set to 5°C off and 7°C on for lager fermentation with
the probe in the bottom of the freezer. Now I realise that the slight estery
taste in my last two lagers is probably because the actual temperature was
something like 11°C + add another 3° or 4° for elevated temps during primary
fermetation and it was too warm.
Now I am thinking of adding some sort of stainless steel tube or
something at about the hafway mark and away from the walls to drop the probe
into to get a better temperature balance in my freezer.
Steve W (in Aus)
|
|
| |
Date: 08 Dec 2006 09:25:00
From: Ranger Steve
Subject: Re: Temp difference in Freezer
|
Mark R wrote:
> "Dick Adams" <rdadams@smart.net> wrote in message
> news:12ni0u258rkmlf7@corp.supernews.com...
> > Steve/Aus <adlab@bigponddotnetdotau.trashthisbit> wrote:
> >
> >> I thought my chest type freezer with electronic external controller
> >> was
> >> running warmer than it should. I had it set at 0=B0C off and 2=B0C on =
with
> >> the
> >> temp probe at the bottom of the freezer. This morning I lifted the pro=
be
> >> up
> >> to about the halfway mark and the temperature was a full 5=B0C warmer!
> >
> >> I normally keep it set to 5=B0C off and 7=B0C on for lager fermenta=
tion
> >> with
> >> the probe in the bottom of the freezer. Now I realise that the slight
> >> estery
> >> taste in my last two lagers is probably because the actual temperature
> >> was
> >> something like 11=B0C + add another 3=B0 or 4=B0 for elevated temps du=
ring
> >> primary
> >> fermetation and it was too warm.
Another idea is to put a thermal temperature strip on your carboy (like
the kind you can put on a fish tank) and manage the temperature of your
carboy instead of the air inside your freezer. When fermentation is
active I'll find the carboy will be 3-4 degrees warmer than the air
inside of my fermentation fridge - so I dial down the temperature on
the controller a few degrees to compensate.
Steve
|
| |
Date: 08 Dec 2006 05:40:08
From: brian@yahoo.com
Subject: Re: Temp difference in Freezer
|
On Dec 8, 1:18 am, rdad...@smart.net (Dick Adams) wrote:
> Steve/Aus <a...@bigponddotnetdotau.trashthisbit> wrote:
> > I thought my chest type freezer with electronic external controller =
was
> > running warmer than it should. I had it set at 0=B0C off and 2=B0C on w=
ith the
> > temp probe at the bottom of the freezer. This morning I lifted the prob=
e up
> > to about the halfway mark and the temperature was a full 5=B0C warmer!
> > I normally keep it set to 5=B0C off and 7=B0C on for lager fermentat=
ion with
> > the probe in the bottom of the freezer. Now I realise that the slight e=
stery
> > taste in my last two lagers is probably because the actual temperature =
was
> > something like 11=B0C + add another 3=B0 or 4=B0 for elevated temps dur=
ing primary
> > fermetation and it was too warm.
> > Now I am thinking of adding some sort of stainless steel tube or
> > something at about the hafway mark and away from the walls to drop the =
probe
> > into to get a better temperature balance in my freezer.My suggestion is=
to put the EEC probe into a cup of alcohol.
> I use gin because I don't think it's fit for human consumption.
>
> Dick
Another option to consider is to put a small fan in the freezer (like a
computer fan) to circulate the air and prevent the cold air from
settling to the bottom. Even a little air circulation should help keep
the temp constant from top to bottom.
|
| |
Date: 08 Dec 2006 06:18:42
From: Dick Adams
Subject: Re: Temp difference in Freezer
|
Steve/Aus <adlab@bigponddotnetdotau.trashthisbit > wrote:
> I thought my chest type freezer with electronic external controller was
> running warmer than it should. I had it set at 0°C off and 2°C on with the
> temp probe at the bottom of the freezer. This morning I lifted the probe up
> to about the halfway mark and the temperature was a full 5°C warmer!
> I normally keep it set to 5°C off and 7°C on for lager fermentation with
> the probe in the bottom of the freezer. Now I realise that the slight estery
> taste in my last two lagers is probably because the actual temperature was
> something like 11°C + add another 3° or 4° for elevated temps during primary
> fermetation and it was too warm.
> Now I am thinking of adding some sort of stainless steel tube or
> something at about the hafway mark and away from the walls to drop the probe
> into to get a better temperature balance in my freezer.
My suggestion is to put the EEC probe into a cup of alcohol.
I use gin because I don't think it's fit for human consumption.
Dick
|
| | |
Date: 08 Dec 2006 13:43:19
From: Mark R
Subject: Re: Temp difference in Freezer
|
"Dick Adams" <rdadams@smart.net > wrote in message
news:12ni0u258rkmlf7@corp.supernews.com...
> Steve/Aus <adlab@bigponddotnetdotau.trashthisbit> wrote:
>
>> I thought my chest type freezer with electronic external controller
>> was
>> running warmer than it should. I had it set at 0°C off and 2°C on with
>> the
>> temp probe at the bottom of the freezer. This morning I lifted the probe
>> up
>> to about the halfway mark and the temperature was a full 5°C warmer!
>
>> I normally keep it set to 5°C off and 7°C on for lager fermentation
>> with
>> the probe in the bottom of the freezer. Now I realise that the slight
>> estery
>> taste in my last two lagers is probably because the actual temperature
>> was
>> something like 11°C + add another 3° or 4° for elevated temps during
>> primary
>> fermetation and it was too warm.
>
>> Now I am thinking of adding some sort of stainless steel tube or
>> something at about the hafway mark and away from the walls to drop the
>> probe
>> into to get a better temperature balance in my freezer.
>
> My suggestion is to put the EEC probe into a cup of alcohol.
> I use gin because I don't think it's fit for human consumption.
>
I would think the more thermal mass you put your probe into (cup of gin) the
larger the temperature swings, and the longer the freezer runs. In a chest
freezer you aren't getting any air circulation so that large a temperature
difference from top to bottom indicates a possible insulation problem.
Raising the probe towards the top would be a semi-fix to the problem but the
bottom of the freezer would be colder than you want. You might want to
reduce the temperature spread to 1 or 1.5C and watch your freezer to make
sure it doesn't "short cycle". You might also want to check the insulation
in the lid of your freezer and try to insulate the top a little better.
Mark R
|
| |
Date: 08 Dec 2006 16:40:19
From: John 'Shaggy' Kolesar
Subject: Re: Temp difference in Freezer
|
On Fri, 08 Dec 2006 06:02:03 GMT, <adlab@bigponddotnetdotau.trashthisbit > wrote:
> I normally keep it set to 5°C off and 7°C on for lager fermentation with
> the probe in the bottom of the freezer. Now I realise that the slight estery
> taste in my last two lagers is probably because the actual temperature was
> something like 11°C + add another 3° or 4° for elevated temps during primary
> fermetation and it was too warm.
Put a stick on thermometer on your fermenter, and monitor that temp during
the fermentation. Set your controller to be whatever it needs to be in order
to keep the actual fermenter temp where you want it. For example, I like
to ferment most ales in the mid-60s. However, in order to achieve that (due
to additional heat created by the fermentation), my controller atually
gets set to the low 60s. It's fairly normal that the controller temp
is going to be different than the temp of your fermenter.
Just eyeball the stick on thermometer during a couple fermentations, and
you'll soon get an idea of what the controller needs to be configured
for. This way it doesn't matter if the probe is at the bottom or top
of your freezer, as long as it's consistently in the same place. The
fermenter temp is what's important.
John.
|
| | |
Date: 08 Dec 2006 23:07:40
From: Steve/Aus
Subject: Re: Temp difference in Freezer
|
"John 'Shaggy' Kolesar" <spam@shagg.net > wrote in message
news:slrnenj5m3.ki2.spam@weizen.shagg.net...
> On Fri, 08 Dec 2006 06:02:03 GMT, <adlab@bigponddotnetdotau.trashthisbit>
> wrote:
> Put a stick on thermometer on your fermenter, and monitor that temp during
> the fermentation. Set your controller to be whatever it needs to be in
> order
> to keep the actual fermenter temp where you want it. For example, I like
> to ferment most ales in the mid-60s. However, in order to achieve that
> (due
> to additional heat created by the fermentation), my controller atually
> gets set to the low 60s. It's fairly normal that the controller temp
> is going to be different than the temp of your fermenter.
>
> Just eyeball the stick on thermometer during a couple fermentations, and
> you'll soon get an idea of what the controller needs to be configured
> for. This way it doesn't matter if the probe is at the bottom or top
> of your freezer, as long as it's consistently in the same place. The
> fermenter temp is what's important.
>
>
> John.
I Think I'll do a bit of all suggestions.
Part of the big difference could have been the ambient temperature of (up
to) 38°C. I like the idea of the fan and as I have a spare 12v fan and a 12v
power supply it is a simple job.
Other than that, what John suggested is concentrate on fermentor temps not
freezer temps makes obvious sense which I stupidly overlooked.
Steve W (in Aus)
|
| |
Date: 09 Dec 2006 04:12:18
From: Sean
Subject: Re: Temp difference in Freezer
|
>I would think the more thermal mass you put your probe into (cup of gin) the
>larger the temperature swings, and the longer the freezer runs.
In the commercial walk-in units that I work with, the techs have
put the probes into a gel in a screw-on type test tube. When I asked,
they said that it kept the compressor from working too hard after just
opening the door (faulty temp reading due to the position of the
thermocouple). I would think that repositioning the probe or immersing
in a more neutral substance (mineral oil?) would help.
Of course, getting a correct temp on the product is essential as
Shaggy pointed out. Air temperature will always be 4-5 deg F lower than
product temperature. The fan can help but the power supply would have
to be outside the cooling space, right? (And the moisture probably
wouldn't help it either).
Sean
|
|
