Back to the topic before Ian goes ballistic...

cafeIKE wrote: For the last while, I've been collecting up the grinder purges through the day and pulling tomorrow's 1st shot with them. Directly into the tray! Let the group sit for a bit to allow the coffee to 'work'.

For the record. I do not produce a shot's worth of waste every day I am careful when making the last shot to grind no more than needed. If there is 3g it is because I pulsed the grinder a bit long to thoroughly and completely blast the old stuff out (MD40 retains very little grind-very small burr set).

cafeIKE wrote:For the non-purging Pollyanna / miser, a few grams in the blind basket works as well.

Ya can't help it... Ya gotta to be derogatory to someone...

So anyway, how much coffee do you think would be required using the "pre-shot backflush" ?

I can already hear the complaints about the increased workload... Some of us don't even want to level their shots before tamping...

cafeIKE wrote:For the last while, I've been collecting up the grinder purges through the day and pulling tomorrow's 1st shot with them. Directly into the tray! Let the group sit for a bit to allow the coffee to 'work'.

For the non-purging Pollyanna / miser, a few grams in the blind basket works as well.

Not quite a quantum leap, but the delta between 1st and 2nd consumable has diminished considerably.
Same improvement on the HX and DB.

Great thread Ian!

My girlfriend thought I was just being nice, always giving her the first shot.

To a much lesser degree, old coffee oil in the grinder may also be a culprit.

It is after reading that same thread (Poll : One Shot Grind Remnants) that I did the coffee remnant check. Although, I didn't do the brutal extraction that some do. Remind me never to buy a grinder from these guys!

Fullsack wrote:To a much lesser degree, old coffee oil in the grinder may also be a culprit.

How would the old oil in the grinder be a culprit?. Assuming that the grinder is pulsed to clear the old stuff... Oh! I get it now. This applies to the "no hopper" single shot grinder's right?

Whale wrote:Ya can't help it... Ya gotta to be derogatory to someone...

Ya gots ta RBTL.

Whale wrote:So anyway, how much coffee do you think would be required using the "pre-shot backflush" ?

I'm guessing you need enough coffee to make an extraction of suitable strength. If using a blind basket, something like 3 or 4g should be enough.

Based on my being a "miser"; I'll give the "3g pre-shot backflush a few try and see.

I may not have written it before but I certainly do suffer from "first shot deficiency syndrome".

RapidCoffee wrote:Unfortunately this has the ring of truth. But the implications are ugly. As in, how long does the machine have to sit before the coated coffee oils get nasty? Sigh. Looks like I may need to rethink my cleaning regimen. Thanks, Ian.

From what I can remember reading coffee oils turn rancid after about 40 minutes, but this is probably more of a scientific fact than a practical matter.

cafeIKE wrote:I'm guessing you need enough coffee to make an extraction of suitable strength. If using a blind basket, something like 3 or 4g should be enough.

I, who always rinse my portafilter after pulling a shot on the La Pavoni, have noticed that if I just dry wipe the portafilter after and leave it for the next morning it will have a quite rancid and disgusting smell. Therefore, I think it would be beneficial just to pull a shot through the portafilter as well to rinse out any old oils from it. Except if you're using a bottomless one of course.

Did it this morning! About 7g of scrap (5g) and good (2g) coffee for the first shot that went in the drip tray. Followed by my normal 3 doubles. Must admit to not seing much of an improvement over the first shot of the previous day. Still can taste and significant improvement in the second shot over the first one. Since this could be for so many reason, it will take a few days of it before I can conclude.

I thought about it yesterday and although the idea may be good; there is something about the "pre-shot backflush" which really does not seem right. I do clear backflush to clean the machine of coffee oil and grinds and now I would purposefully throw old grind in there!

O.K. with sinking the first shot, on a trial basis for now, but the backflush with old coffee? I do not think so.

Edited: Day 1

Stuggi wrote:From what I can remember reading coffee oils turn rancid after about 40 minutes, but this is probably more of a scientific fact than a practical matter.

I'd guess neither. ground coffee goes stale in about 40 minutes, but it doesn't taste rancid when you brew it; I don't think rancidity is big factor with coffee oil that's in coffee grinds sitting at room temperature. The heat of the grouphead would naturally accelerate the processes whereby oil goes rancid, so it will be much faster there.

Whale wrote:I thought about it yesterday and although the idea may be good; there is something about the "pre-shot backflush" which really does not seem right. I do clear backflush to clean the machine of coffee oil and grinds and now I would purposefully throw old grind in there!

Why does this bother you? A clear backflush of water will pass right over the old coffee oil--as mentioned, oil doesn't dissolve in water. So you have to use detergent or more oil, whichever you prefer. If this rancid oil bit is true, the water backflush is a total waste. And as for the old coffee bit, if backflushing with old coffee seems bad, why not try grinding 2-3g of fresh-ground coffee instead?

Whale wrote:How would the old oil in the grinder be a culprit?. Assuming that the grinder is pulsed to clear the old stuff... Oh! I get it now. This applies to the "no hopper" single shot grinder's right?

Yep.

cafeIKE wrote:I'm guessing you need enough coffee to make an extraction of suitable strength. If using a blind basket, something like 3 or 4g should be enough.

The approximately 4 grams of fresh coffee I ground into the blind basket this morning was plenty, made a big difference. Good discovery Ian.