[Homeroast] Homeroast Digest, Vol 37, Issue 5

sci scizen at gmail.com
Sat Feb 5 14:52:56 CST 2011

That makes sense. I get it. The Amp meter gives me a relative measurement. I
have used that same method with temperature measurements in the past with
other roasters.
Everything in my house runs hot and fast at 125v. I live about 500f from a
power substation.
Thanks for reassurance on the heating elements. I try to never push anything
technological to its utter extremes. "Easy does it" is my motto. I will get
a Killowatt to measure the actual wattage being used. I know some of that
will be for the motors and fans.

I have been using 7A for 125-150g batches; 7.5A for 200g; and 8A for 225g. I
reach 1C in the 9-11 minute range. I did 225 g of Classic Mandheling and I
had no problem getting to 2C at 15:00 and 438BT. I have not been able to
record ET reliably just yet. When I do measure it with my 2nd TC, it is
usually a good deal higher. I need to get a dual input unit.  I have done
about 15 roasts w/out the thermal blanket, and about 10 with it. The
blanket, IMHO, aids the thermal transfer, makes the unit behave more
steadily, gives it thermal momentum. When I plot my  roast curves, they are
a pretty consistent, very similar. I'm still in the learning curve on how to
manipulate the curves. I get a nice long pause between 1C and 2C hitting 2C
in the 14 to 16 minute range. I have been doing what Tom suggested: leave
the power setting alone and using the fan to manipulate the curves.

A dumb mistake to avoid: I accidentally hit the door lever on the QM3 just
as my Classic Mandheling was entering 1C, releasing about 25% of the beans
into the cooling tray. Not good. The door got stuck open with beans, and
more poured out. I managed to get the door closed again. Determined not to
ruin the roast, I quickly  dumped the escaped beans back into the loading
chute. This incident caused a big dip in the roast curve, but the Q quickly
gained momentum and got them up to 2C.



> Date: Sat, 5 Feb 2011 12:07:33 -0500
> From: "Mike Chester" <mchet at charter.net>
> To: "A list to discuss home coffee roasting. There are rules for
>        thislist,       available at
> http://www.sweetmarias.com/maillistinfo.html"
>        <homeroast at lists.sweetmariascoffee.com>
> Subject: Re: [Homeroast] Quest Amp Question
> Message-ID: <D051392A3EF04AFAB299EE840DB4D2F6 at mchet>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>        reply-type=original
> You are correct - 1250 watts.  You are not hurting your element. The
> nameplate ratings are only an average for many units.  They are built
> within
> a tolerance and your actual unit may be higher or lower within that range.
> Also, I am sure that the built in ammeter is only approximate.  You would
> need a more accurate meter to get the real reading.  The meter is there as
> a
> reference, not an absolute value.  As long as it reads consistently, it
> does
> not matter if it is correct unless you are giving your profiles to another
> Quest owner.  As an example, let's say that it was off by 50% (it is
> probably off by less than 10% but I am trying to make a point)  If would
> show 5 amps when the real current was 10 amps every time. Since your real
> concern should only be the roast results, you would dial in 5 amps every
> time instead of 10.  The beans would not know that your meter was wrong,
> and
> you shouldn't care.
> If you really are running at 1250 watts, your element should be fine.  They
> are made heavy enough to handle a small over-power without any problems.
> Remember, the nameplate rating is only nominal and your actual results may
> vary.
> I hope that I have explained this clearly.
> Mike Chester

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