AndyS wrote:You are correct when referring to the particular type of flowmeter in the picture, which is called a "rotometer." I thought it was an appropriate choice because it is simple and inexpensive. Not only must the meter be inline, but it must be mounted vertically, and the gas must enter at the bottom and exit out the top. This means, as you say, that the gas piping must be designed to accommodate it....

OK - I was actually thinking of a different type, but now that I look at this one it seems even more attractive (at under $100). I'd need to plumb a little "loop" into the line, but as Andy indicated that is fairly trivial and can be done with materials found at my local hardware store.

JonR10 wrote:now that I look at this one it seems even more attractive (at under $100)

Sorry, I made a mistake: the one I was looking at (#41945K55) has too high a capacity (2.2-22 cubic feet per MINUTE). I believe 2.2-22 cubic feet per HOUR is the appropriate range for a small roaster.

The good news is McMaster #5079K26 is rated for the lower range and is budget priced at $38.94 without the redundant control valve. Maybe someone will try it and report back.

AndyS wrote:Sorry, I made a mistake: the one I was looking at (#41945K55) has too high a capacity (2.2-22 cubic feet per MINUTE). I believe 2.2-22 cubic feet per HOUR is the appropriate range for a small roaster.

The good news is McMaster #5079K26 is rated for the lower range and is budget priced at $38.94 without the redundant control valve. Maybe someone will try it and report back.

Hmmm....I was looking at the manufacturer's website and had selected FL2005 (2-20 SCFH) for $49. I'm thinking this will work perfectly well, and I like to have the redundant control valve because the valves in these meters tend to be more precise.

JonR10 wrote:I was looking at the manufacturer's website and had selected FL2005 (2-20 SCFH) for $49. I'm thinking this will work perfectly well, and I like to have the redundant control valve because the valves in these meters tend to be more precise.

Omega offers a nice selection. Have you considered the FL2033? It's almost twice as tall, so the scale will be easier to read. $61 with valve.

Looking at these nice meters is almost enough to get me back into home roasting.

AndyS wrote:Omega offers a nice selection. Have you considered the FL2033? It's almost twice as tall, so the scale will be easier to read. $61 with valve.

Even better! I just palced my order.
Thanks!

JonR10 wrote:Even better! I just palced my order.
Thanks!

Palcing is now illegal in most states; I hope you will reconsider.

ken

Ken Fox wrote:Palcing is now illegal in most states; I hope you will reconsider.

ken

LOL - I will use the excuse that I am recovering from a tequila tasting party last night

Found a nice burner while wandering Lowes today:


Its expands from 14.25" to 18" and should be appropriate. Its a generic grill burner replacement part and cost $15. I could do this on a drill press but not worth the effort.

As for the flow meter, it will simply be a more intuitive control method for heat input. A pressure gauge, properly installed, should be just as repeatable. Since I'm building it from scratch, and flow is the variable in question, I will use a flow meter. As an engineer, I will sleep better knowing my process is being controlled by the real process variable, not one removed by an empirical relation, but thats just my handicap.

Yesterday I did some experimenting with "slow start and faste finish" on my Diedrich hr-1.

I picked out two different coffees to try this on. The coffees I roasted was Ethiopia Guji Oromo from SM, and the Guatemala Villa Lupe also from SM. The Ethiopian I have developed a profile for earlier, but I havent been very satisfied because of a bitterness/burned flavour in the cup. This profile had 1st crack at 8.30 - 9 min, and 4 minutes to finish. The new profile for the Ethiopian have 1st crack at 10.30, and a 2 min 45 sek finish. Earlier attempts with shorter finish, has given a too high level of acidity. So the old profile forced me to increase the finish to 4 min to control the acidity. Today I brewed the coffee from the new profile, and I was expecting an acidity bomb. But It wasnt too acidic at all. It was a smooth, sweet and clear cup. And the ashiness and bitterness was vanished. For me this was a great improvement in the cup. The Guatemala villa Lupu didnt come out that great. It had 1st crack at 11 minutes, and a 3 minute finish. This was undeveloped/grassy, bitter and acidic, I will try even longer to first crack the next time and see what happens.

The Ethiopian had first crack at 189 celcius, and I dropped it at 208 degrees Celsius. I followed the Diedrich recommendations on airflow, 50/50+ at 280 F, but waited with RD til 197 degrees Celsius - I couldnt loose momentum during first crack since I was finishing faster than usal. I also put the heat to Medium at the start of 1st crack. But the question is how does this work with espresso roasts. If Im gonna get to a full city roast with 3 minutes finish, I really have to push a lot of heat on the beans. I will try this with a brazilian natural next week and see what happens in the cup.

My roaster is electric, and cant be compared to the gas roasters - but the user manual for my roaster gives the same recommandations as for the gas roasters. The biggest difference is the reaction time when adjusting the heat. Airflow is identical.

I have continued roasting following Steven Diedrichs roasting profile, this have really improved my roasting. I am now roasting with 2-3 minutes finish (after 1st crack). I have found that for my Diedrich Hr-1, the 1st crack window is more 10-12 minutes, than 11-13 that is recommended for the ir-1. This is probably because the Hr-1 is drying the beans more in the beginning of the roast due to a higher turning-point. I did the El Salvador Siberia Estate Bourbon to a city+ roast, 11.15 til 1st crack, then 2.20 finish. The result was a bit undeveloped coffee, I will try to increase the finishing time to 2.45 next time. The Rwanda Remera Nyarusiza, I roasted 9.45 to 1st crack, and 2.45 to finish. This is by far the best roast so far. The Ethiopia guji oromo was roasted with 10.13 to first, and 2.15 to finish, this roast also came out well. Roasted to a city/city+.

It seems to me that when testing new coffees 2.30-3 minutes will be the finish times to try first. For small beans like yirgacheffe, it works with 2-2.30. Guatemalans seems to need more time before and after first crack do develop enough.

I am following the diedrich recommandations on airflow, 50/50 at 138 degree Celsius, and RD at 180 degree Celsius - 1st crack at approx. 190 degree Celsius. I keep the heat at high til about 30 seconds after first, then go to medium. Some coffees need a kick in the butt to preserve momentum, then I go back to 50/50 approx. 10 degree Celsius after 1st. Airflow is byfar the best way to control heat on the Hr-1.

I look forward to hear what other Diedrich users have come up with in experimenting with slow start/fast finish.

I have been roasting for drip only, havent tried for espresso yet.

BTW: here is a link to discussion about roasting on the Diedrich ir-12, maybe some of this info may be interesting to the ir-1 owners:

http://www.baristaexchange.com/group/ro...drich-ir12