HomeRoast Digest


Topic: My Rosto (89 lines)
1) From: miKe mcKoffee
Reply to both your offlist and onlist posts - they're below my reply
(onlist):
First, I think questions about roasting problems/techniques are best
addressed onList where multiple people with varied experiences can answer.
Stock Rosto normal ambient temps I think I'd say not, the Rosto normally
wouldn't have a slow finish to the roast. I haven't roasted stock Rosto for
a couple years. Extreme difference in degree of roast for a bean like CR I
think would indicate lack of proper bean movement, should just move when
green and speed up to a nice slow swirl by 1st. Your onlist post may have
illuminated another problem. It sounded as if you're comparing roasting
results/behaviors in vastly different ambient temperatures. All roasters
(all cooking for that matter) is affected by temperature. Air roasters
intake environmental air and blow it past the heater. The heater element is
not fixed temperature, but a temperature difference resistive element which
gives off heat dependant on the voltage applied. (makes sense to me anyway)
Constant voltage will give the same heat for same ambient temperature. Other
factors are air flow acting to cool the heater. Greater air flow, less heat.
Which is why faster moving beans will not get as hot or roast as dark as
slower moving beans for the same temperature heater. Hence batch size can
cause higher or lower max roast possible too.
The biggest thing you can strive for is consistency in start of batch barely
moving bean movement, consistent voltage and controlling ambient
temperature. If roasting outdoors or in cold gargage, 20f ambient will
behave much different than 70f ambient. Maybe not even make 1st crack. But,
stock Rosto with proper voltage and batch siz can roast in temperatures in
the teens. I did it using the box method. (pre variacs etc) I used about a
2x2x2' box with the top removed and one side cut like a *drawbridge*. I
faced the Rosto exhaust towards the drawbridge and varied how far opened or
closed to keep the inside *comfortably* warm. Lowest temp I tried this
method was 17f, no problem. (would have tried colder but it didn't get
colder:-) This was straight stock Rosto. Just a cardboard box is all that's
needed to maintain stock Rosto roasting in freezing temps.
It's easier, for me, to roast in any temp with split wired boosted variable
voltage control. Below freezing I had blocking of the exhaust slits in
varying amounts to increase the recirculated air amount. This is without
box. (if I had it to do again I would have purchased a different varica, my
heater variac would have had 20% rather than 10% max boost. As it is my max
heater voltage is 132v, my fan is 20% variable boost or about 144v)
I think I'm rambling so....
Kona Konnaisseur miKe mcKoffee
MCSE (Maniacal Coffee Systems Engineer/Enthusiast;-)
URL to Rosto mods, FrankenFormer etc.http://mdmint.home.comcast.net/coffee/Rosto_mod.htm


HomeRoast Digest