On swarf: does the Fuller brush man sell any 30awg brushes?

(sorry I couldn't resist)

Here's one that surprised the hell out of me, and bound to raise some eyebrows. As I started testing Greg Scace Portaroid (name still in progress), I have learned something interesting: It is reporting a much wider temperature variation within a shot than I expected. A typical variation on the machine I tested was 1.6-2f from the 10th second on. A ristretto will reduce it, but I was checking 60 ml flow in 25 seconds - a double. (it is fixed on the Thermofilter).

However, if I ran the shot on a cold P/F, the variation shrunk to 0.8f. About half. I consistently repeated the experiment, using the same flush routine, and repeated the result. The brew temp I reached was ~1.5 f lower than one I would reach had the P/F been in the machine at all times. However, it was repeatable.

The Thermofilter uses a bottomless P/F that has less mass than a regular one. My conclusion is: at least for a bottomless P/F, on a dual boiler machine, keep it at room temperature at all times.

Perhaps this is the perfect example of the limitations of science in an arena that combines both science and art.

Abe Carmeli wrote:at least for a bottomless P/F, on a dual boiler machine, keep it at room temperature at all times.

You're assuming that the smaller the temperature variation as measured by the Thermofilter thingie, the better the shot.

Where's the evidence for your assumption? Just cause Schomer says it, doesn't make it so....

So......

How does the coffee taste?

terryz wrote:So......

How does the coffee taste?

Coffee? What coffee? Don't confuse me with the facts Terry, I'm too busy looking at thermometers here.

Abe Carmeli wrote:It is reporting a much wider temperature variation within a shot than I expected. A typical variation on the machine I tested was 1.6-2f from the 10th second on. A ristretto will reduce it, but I was checking 60 ml flow in 25 seconds - a double. (it is fixed on the Thermofilter).

However, if I ran the shot on a cold P/F, the variation shrunk to 0.8f. About half. I consistently repeated the experiment, using the same flush routine, and repeated the result. The brew temp I reached was ~1.5 f lower than one I would reach had the P/F been in the machine at all times. However, it was repeatable.

The Thermofilter uses a bottomless P/F that has less mass than a regular one. My conclusion is: at least for a bottomless P/F, on a dual boiler machine, keep it at room temperature at all times.

your conclusion does not necessarily follow from your evidence. it sounds like you're rejecting the results of the first method simply because you prefer the results of the second method. using a cold test instrument will pull some of the heat from the brew water sample, which would give you both a lower overall temp indication as well as attenuate some of the temp fluctuations.

Barry wrote:your conclusion does not necessarily follow from your evidence. it sounds like you're rejecting the results of the first method simply because you prefer the results of the second method. using a cold test instrument will pull some of the heat from the brew water sample, which would give you both a lower overall temp indication as well as attenuate some of the temp fluctuations.

I believe you lost me there. Do you mean to say that I prefer an 0.8f temp variation to 1.6f, and that preference dictated my conclusion? If so, you are perfectly right. And my followup question is who doesn't?

Abe Carmeli wrote:I believe you lost me there. Do you mean to say that I prefer an 0.8f temp variation to 1.6f, and that preference dictated my conclusion? If so, you are perfectly right. And my followup question is who doesn't?

my point is it is very likely the .8F temp variation isn't. it's very likely you're getting the same 1.6F variation, only attenuated by thermal losses to the <cold> instrument.


--barry "rose-colored glasses"

Abe Carmeli wrote:My conclusion is: at least for a bottomless P/F, on a dual boiler machine, keep it at room temperature at all times.

Abe, are you saying the portafilter AND the thermofilter were cold?

I ask because Terry sent me a thermofilter for evaluation. I started with the bottomless portafilter in the group (hot) with a normal basket. Later I swapped in the thermofilter and noted the readings indicate it has greater initial thermal mass than the equivalent coffee + basket. That is, the readings from the thermofilter were not consistent with the profile I would expect from an "over the basket edge" measurement until the thermofilter was hot. Not surprising given the brass fittings, but implies cold instrument measurements are suspect at best.

terryz wrote:So......

How does the coffee taste?

I am pleased to say this morning's was the best in recent memory. Really, really good.