Ok ! I started my testing with basics.
Test 1 : Basic fire & smell test of the exhaust :
The idea was to make sure the charcoal I'm using is fault free ( I know this is well reviewed but wanted to eliminate a bad batch reason ). Also wanted to rule out the fire starter I used out of the equation.
thought to do this as a dry run without food so I could repeat couple of checks.
1) Built a small heap of Headbeads lump and fired using a cotton ball with vegetable oil ( just some technique I saw online . My butane torch is still on it's way from amazon ). Was bloody hard to get it started though.
2) Waited 10 minutes till I saw the cotton ball disappear and lump caught fire. while it still had flame I closed the lid and set Top & Bottom vents fully open for 20 mins.
The first 10 minutes it emitted a medium thick white/grey color smoke. ( must be the VOCs burning out and startup smoke of the charcoal ).
I held my hand over the exhaust and smelled it : had a light fuel smell ( indicating partial burn) . not too bad though.
3) Closed the top Vent block keeping the daisy wheel holes open. Button vent at 2/5. Didn't place the deflector as this was just to watch the charcoal smoke and smell.
in around 30 mins, the smoke thinned out to a light vapor stream.
Did a exhaust smell check - it smelled much clean ( desirable )
I then set the Top vent to 70% and then left it for another 20 mins. It settled at 240 F without a visible smoke. (total time : 50 mins )
Did a exhaust smell check - it smelled same as above ( clean )
Closed the vents and let it cool down.
Test 2: Fire lighter cube check
I lit a new fire . This time I lit it with the lighter cube ( Red Head started ) and waited 15 mins before closing the lid and repeated above.
After around 30 minutes I checked the exhaust :
The results were pretty much the same as above. Thin smoke , smell of a clean burning charcoal at the exhaust . No specific nasty smell from the lighter cube ( must have burned off completely ).
*I will not use that lighter cube again. Just wanted to rule it out in my specific problem. it starts with a nasty smell and so I totally agree that it would taint the interior of the cooker and affect the food in the long run as you guys said.
Test 3: Smoke wood check
Performed the same test as above , this time I thought I would add a piece of smoke wood and do the 'exhaust check'
I split a piece of apple wood ( Fornetto chunks from Bunnings ) into three pieces. The chunk is like 5 cm x 10 cm each.
1) Lit the fire with a medium pile of charcoal. ( repeated the above steps )
2) In around 20 mins Set the top vent block closed but daisy wheel fully open , bottom vent at 2/5
In around 40 - 45 mins the temp was at 200 F, exhaust was clear , the fire patch was ok but looked like still settling.
4) at 50 mins , I added a piece of smoke wood just above the fire patch. the 'smoke' started almost immediately.
interestingly the smoke was never 'thick white' which I saw in other days ( must be due to I added the smoke wood much earlier previously, where the lump was still getting into a proper burn rate.).
The starting smoke was like light grey ( not white ) but visible . but it had the 'eye burning' strength. ( I think it was still getting settled )
Did a exhaust check and I could smell the raw / harsh smell of apple wood in my palm . As per my memory it was less crude than the previous times where I added a full chunk and much early in the process.
4) In around 60 minutes ( 10mins after adding wood chunk ) , the smoke thinned out but still visible when close to the top vent
Question :
Is the above what's called 'Thin Blue Smoke' ? or does it have to thin out even more ?
5) I left it for another 15 mins , (1.15 Hrs since the start of fire ) - and did another exhaust check . This time the smell was less strong. I guess this is as good as it gets .
Question : Is the time point of time I should add the meat ?
( In around 3 mins if I check the palm I could smell the apple wood smoke after the other compounds has vaped off ( very desirable ) ) .
Question :
I guess at the exhaust smoke, the smoke is sort of concentrated so it smell stronger. Is this right ?
6 ) Left the fire for another 30 mins and still could see a 'faint' smoke and exhaust check was same as above.
7) I opened the lid and checked , the wood piece was almost turned into dark color charcoal. I then added another piece and observed the same as above.
Just wanted to repeat the test and see I get consistent results,
My comments:
- The charcoal seems to be fine
- The fire starter cube doesn't seem to be the cause I got the strong taste ( I will not use it in future anyway)
- Looks like the source of the strong taste is adding the smoke wood. May be too early or too much. ( Would need to figure this out in next few tests )
- Did not check the drippings on the deflector in the above tests as they were just dry runs.
*The biggest thing I reinforced myself is that I should wait till the fire patch is at a good burn rate ( at least 45 mins after lighting with my fuel load and Vent settings ) before I add the wood chunk. It does n't give a white smoke at all. Starts with a medium grey smoke and thin out quickly. I did n't see a 'blue' tinge but the smoke thinned out until I had to close up to the vent to see it properly.
*what I did earlier in my strong tasting cooks: I added the wood chunks at around 30 mins instead of the 45 - 60 mins mark. I only saw the thick smoke white / grey with charcoal starting and it thinned out in around 20 mins from the startup.( So this is the take away point for me from you guys, Thanks so much )
In my previous attempts although I remember like I waited till the smoke thinned out like above to put the meat on, it may have still had a strong smell at the exhaust. And also I remember that each time I opened the lid for some reason, the fire stoked and gave white smoke for a while before thinning out. ( This could have been absorbed /coated on the meat as creasote in my guess ) .
I will do another test with and without smoke chunks with some meat tomorrow :). Will use the cotton ball to light the fire and use a foil to cover the deflector so it leaves the drippings out of the scene.