Voltage or Ambient Air Temp

[Steve Freides]

I'm still home roasting using a popcorn popper. I don't get
consistent results because, I think, of voltage variations in my home.
E.g., I am roasting on a table near a window in my basement - small
exhaust fan set up in a nearby window, another window open across the
basement to let air in. I roast 3 batches and get great results, then
come back an hour or two later and cannot seem to get my coffee hot
enough to do what I like, which is hit second crack in about 7
minutes. Sometimes the same coffee in the same popcorn popper roasts
beautifully in 6-8 minutes, but at other times it takes up to 15
minutes and feels like it's just barely getting there.

We roast a lot of Sumatra and my wife likes it pretty dark - a rough
guideline is that we stop when we see smoke starting to pour out of
the machine, somewhere just shy, but not by much, of a full French
Roast.

I'm considering buying a variac but I'm also considering buying
another coffee roaster. Are there any out there on the market - at
home, not pro, prices - that deal well with variations in electric
current? I think my ideal coffee roaster lets me describe, via its
programming, what sort of roast I want and then delivers that,
regardless of ambient temperature and voltage. Does such a thing
exist, or would I want the variac, regardless. A variac is about a
$100 item that, if it's going to be essential for any home coffee
roasting, I might get next rather than a new roaster.

Many thanks in advance for your opinions and advice.

-S-

[Maryann & Dave]

I don't have answers to your questions, but do have related information.

I used to roast with a hot air popcorn popper, and when I found that it was roasting way too hot, I bought a variac and used that for a couple of years. Then my variac died, and I decided the advantages of a real coffee roaster were worth spending the money on. I've been using a HotTop ever since.

When I write that the popper was too hot, I mean that it was bringing my coffee to the start of second crack within 5 - 6 minutes. I was following the gurus writings religiously, and their experimentation lead to the belief that 12 minutes was a much better total time, and that following a particular temperature profile to that point made a significant difference to the taste of the coffee. I'm certainly not a super-taster, but I am very happy with coffee roasted that way. I was able to follow such a profile by using my variac to adjust voltage during the roast. Of course now, with my HotTop, I build the profile and save it to memory in the machine, and don't have to be tracking temperature every half-minute along the way.

My wife and I prefer our coffee roasted to less than French, generally FC+, but with some varieties (determined by Thom at Sweet Maria's) to as little as C+.

Dave S.

[Steve Freides]

This is very helpful. One specific question - does using the Hot Top,
which I believe tracks the actual temperature of the coffee beans
(please correct if I'm wrong) eliminate the need for the variac? In
other words, if the voltage drops, it will just roast a little longer
or otherwise compensate so that the desired result is obtained
regardless of line voltage?

FWIW, when my batch takes about 7-8 minutes to complete, which means
it's in the middle of the second crack, I'm very happy with what our
coffee tastes like. So far, and probably this is just a quirk of the
air popper, when it takes 12 minutes or so, the results aren't nearly
as good.

-S-

[Maryann & Dave]

Again, I don't have that specific information,
I didn't buy another variac after mine died.
I am not aware of significant line voltage variations in my neighbourhood.
The profile I created and use with the HotTop takes about 12 minutes until FC+ is reached.
The bean temperature as measured by the HotTop is not accurate, so I have drilled a hole and insert my own thermometer to keep track of bean temperature. Building the profile using my own measurements results in a reliable roast which follows that profile automatically.

Dave S.

[scott stap]

I used to roast my beans in the bathroom sink (put the popper in the sink). Two reasons for this, one the bathroom has a fan to suck out the smoke, the other is the sink would actually redirect some of the hot air back into the popper and it would get hotter making the roasts shorter. I noticed that if I did my roasts in the morning it would take longer then if I did them in the afternoon. I tried different things but the results were consistent...

What I found out....

My son would be getting ready for school in the morning and had his space heater on... It was on the same circuit as my popper... Lack of electricity caused the long roasts.

Suggestion: Put a volt meter on your supply line to see what is going on.

Scott

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[Steve Freides]

Thank you both.

We have crappy electricity here, for lack of a more detailed and technical explanation.  It blips off for very short periods of time, sometimes once or twice a day for weeks on end - enough to cause all the backup devices to kick in.  We've called the electric company, and they even put some sort of meter on our house for a few weeks once, but they said they're nothing wrong and that was the end of it.

A variac sounds like a good thing to have, anyway, and since they seem to run $100 for a 20 amp model or thereabouts, I may just get that before I spend $1000 on a dedicated coffee roaster.

-S-

[JimG]

I'm not familiar with any home roasters that will compensate for voltage variations by "automagically" extending or shortening segments of the roast profile.

The Hottop B might be a good option for you, however, as you can manually make the necessary heater adjustments if your voltage is sagging.  You might, for instance, normally run the heater at 90% on the ramp to first crack (FC).  If the voltage is sagging that day, then you could either change this to 100% or live with a slightly longer ramp to FC.

A little (around 2 min) before FC, I drop the heater output to 50% or 60% on my Hottop in order to set the roaster up for a slower ramp between FC and second crack (SC).  I base the timing of this power reduction on the bean temperature, so if the voltage is sagging that day then the ramp to FC might be just a little longer.  I don't care so much about small variations in the timing, as long as the heater adjustment is made at the correct temperature.

Then I adjust the heater power up or down between FC and SC in order to maintain a slowly rising (10F per minute) BT.  So these adjustments are fairly independent of voltage fluctuations.

With the Hottop, it helps very much to have added your own ET and BT thermocouple probes.  But even without doing this I think you can still make adequate on-the-fly adjustments using the stock thermometer.  If you seriously consider a Hottop then I would only recommend the B.  IMO, the P is not a very usable model.

The Hottop is also very flexible when it comes to more extensive mods, if you ever get to that point.  I have mine set up (using a supplemental control board and free RoastLogger software) to perform essentially automatic profiling.  The software makes decisions based on BT and the elapsed time after FC to make the heater and fan adjustments that I want.

Jim
www.coffeetronica.com

[Steve Freides]

Jim, it sounds like you know what I need to know but I confess a lot of your message contains abbreviations that are unfamiliar.  What's the B and the P models?  I'll guess the "P" is the programmable and the B is the less expensive.  What are ET and BT?  BT is bean temperature?

My interest is in being able to start the process and walk away.  It sounds like your mods allow you to do just that - very interesting, indeed.    If I have to monitor my line voltage, I'll just get a variac, which it sounds like I'm going to do, anyway.  

-S-

[JimG]

Hi, Steve -

ET = environmental temperature.  This is normally the temperature of the air at the hottest spot inside the roast chamber.

Yes, the B is the less expensive.  But most Hottop users feel it is the better roaster nonetheless.

"Walk away" is fine as a figure of speech, as long as it doesn't mean you leave the roaster unattended ;-)  The fire risk is simply too great to leave any roaster unattended.

I am pretty close to a situation of being able to set up the roast in advance and sit back and watch.  For a new bean I usually need to play with the drop in temperature, and perhaps the power settings after first crack. But I enjoy tweaking things during the roast and observing the resulting profile.  That is part of the hobby for me.

Maybe the closest home roaster (stock configuration) to set-it-and-watch-it would be the Behmor, although it is going to be affected significantly by voltage variations unless you go the variac route.

Jim
www.coffeetronica.com

[Steve Freides]

Yes, I don't mean literally walk away - I roast at just over arm's length from my desk.  I'm around when the fires start. :)

It sounds either model, combined with a variac, might do what I want.  Do your modifications read BT and ET better than those built into the P model?  Is that why you do what you do?  It seems as if the P model did what it says it does, that would be all one would need.

-S-

[pedxing]

Wow, all this fuss just to roast coffee!

Dog Bowl + Heat Gun, cheap/easy/reliable.

Yes, it's a little more hands-on than a dedicated roaster, but it can't be beat for simplicity, cost, flexibility, reliability, control and most importantly - RESULTS.

But it sounds like you're into fussing around more than anything else, so I'll just quietly back out now...

-pedxing

[JimG]

Steve wrote:
>
>It sounds either model, combined with a variac, might do what I want.  Do your modifications read BT and ET better than those built into the P model?  Is that why you do what you do?  It seems as if the P model did what it says it does, that would be all one would need.

>

>

I don't necessarily think you need a variac with the Hottop B.  It would not hurt, but I think it might be an unnecessary extra expense.  Instead, compensations would be made for voltage fluctuations indirectly because you would base the timing of power changes on the temperature, not on the time.

Yes, added BT and ET thermocouples work much, much better than the built-in sensors, either on the B or the P model.  The P model is not popular among its users, in general.  I think the reason is because it simply turns off the power when the target temperature for a particular segment has been reached?  I am not an expert on this roaster, but I have read enough online accounts from knowledgeable users to understand that it has significant limitations.

I would encourage you to do some more online research regarding the P before making the commitment.  You might also look for posts by RandyG or Home-Barista.com or coffeegeeks.com regarding his experiences with the P and B models.

Jim

[JimG]

No argument.  Been there, done that.  HG/DB worked well, but I was interested in being able to have more control over the roast profile.  And I got a little weary of the chaff flying everywhere ;-)

Jim

[Steve Freides]

I'm "into" learning what my options are before I spend my money.  "Fuss" to me would be having to stand there and move the heat gun when I could be doing something else while minding a timer.  To be honest, I find your comment rude.

To each his own.  I wish you, your heat gun, and your dog bowl good luck and good coffee.

-S-

[North L. Sullivan]

The heat gun/dog bowl is a proven method that produces good results in the hands of a skilled operator.  The heat gun/bread machine
produces good results with less effort.  If you want to spend $100 and up, have at it.  There are plenty of options.  I've spent thousands of
dollars on a roaster (Diedrich 12k) and a dollar on a roaster (popper).  Money spent is less important than focusing on the process.  Even on
a Diedrich, you can screw up by doing something else while roasting.

North Sullivan

On 01/17/2013 08:40 AM, Steve Freides wrote:

[pedxing]

Wasn't my intention to be rude.

But IMO, spending a bunch of money (or time) on a machine, then having to worry about the line voltage is what I consider "fuss".

BTDT.  IMO, all of the home roasting machines are a waste of money.  Too sensitive to too many variables from line voltage to ambient temp to chaff content for them to work reliably, and the batch sizes are so small that you have to "fuss" with roasting more often than should be necessary.  But I guess everyone has to get there in their own way.

Hope you enjoy your journey.

-pedxing