Water Activity/Shelf LIfe

[pastrygirl]

14 hours ago, Kerry Beal said:

Of course we could do it with a Hershey bar or something except I think the Canadian ones are still made in Canada so might not be exactly the same. 

 

Maybe Lindt bars would be the same across north america and easy to find for both of us?

[Kerry Beal]

3 hours ago, pastrygirl said:

 

Maybe Lindt bars would be the same across north america and easy to find for both of us?

Funny I was thinking exactly the same thing - shall send hubby out to get a Lindt 70% Excellence when he gets a chance. 

[Kerry Beal]

17 hours ago, Kerry Beal said:

Funny I was thinking exactly the same thing - shall send hubby out to get a Lindt 70% Excellence when he gets a chance. 

here’s the one he’s picking up 

 

[Kerry Beal]

So here's what I got - I didn't calibrate today - I had done so not that long ago.

 

Half as much water as chocolate - Aw 0.88 - Pro-Choc's estimate 0.96

one quarter as much water as chocolate - Aw 0.78 - Pro-Choc's estimate 0.87

 

Heintz Ketchup - 0.83

Invert (trimoline) - 0.68

 

 

[Rajala]

Haha, this is funny. I can measure for fun too.

 

I have a cheap meter from China and an Aqualab 4TEV Duo.

[DomDeFranco]

This is very cool. Thanks to everyone taking part in this experiment!

 

@Rajala I was wondering if you've done any experiments yourself comparing your 2 meters as I was looking to get one of those cheaper Chinese ones but wasn't sure how accurate they were? They say +/-0.02 AW accuracy on the description but, i've no idea how true that is.

 

@Kerry BealWhat do you think of those Pro-Choc estimates? They seem pretty off at first glance.

 

Thanks

[Rajala]

The Chinese one is pretty accurate based on its specs, but it takes like an hour to get the correct measure. And yeah, it's 0,02 in accuracy which is kind of bad if you get a 0,85 reading. Is it 0,85? 0,87? 0,83?

[DomDeFranco]

35 minutes ago, Rajala said:

The Chinese one is pretty accurate based on its specs, but it takes like an hour to get the correct measure. And yeah, it's 0,02 in accuracy which is kind of bad if you get a 0,85 reading. Is it 0,85? 0,87? 0,83?

Thanks for the quick reply. I think the Aqualab PawKit model claims the same 0.02+/- accuracy but in the UK it's 10 times the price of the Chinese ones and unfortunately I can't afford that, let alone any of the more accurate models.

 

For me, it's a choice between a Chinese meter or a pro-choc subscription and pro-choc's AW estimates don't seem that great. Waiting an hour for a reading, while annoying, isn't a deal breaker for me.

 

Thanks for your help.   

[Kerry Beal]

2 hours ago, DomDeFranco said:

This is very cool. Thanks to everyone taking part in this experiment!

 

@Rajala I was wondering if you've done any experiments yourself comparing your 2 meters as I was looking to get one of those cheaper Chinese ones but wasn't sure how accurate they were? They say +/-0.02 AW accuracy on the description but, i've no idea how true that is.

 

@Kerry BealWhat do you think of those Pro-Choc estimates? They seem pretty off at first glance.

 

Thanks

I’m surprised - when I did similar comparisons with ganaches in the past the numbers were pretty similar 

 

 

[Rajala]

I got 0,6347 for European made invert sugar, trimoline style.

 

European made Heinz ketchup = 0,916.

 

No sure why the reading is that much higher? Less sugar? Different sugar types?

[Kerry Beal]

24 minutes ago, Rajala said:

I got 0,6347 for European made invert sugar, trimoline style.

 

European made Heinz ketchup = 0,916.

 

No sure why the reading is that much higher? Less sugar? Different sugar types?

My bottle has been open for a while and it was ‘well aged’ before I opened it - so perhaps not the best example. But I’d be willing to bet that European Heintz is lower in sugars 

[DomDeFranco]

12 minutes ago, Kerry Beal said:

My bottle has been open for a while and it was ‘well aged’ before I opened it - so perhaps not the best example. But I’d be willing to bet that European Heintz is lower in sugars 

Yeah, i think the US version has corn syrup whereas the UK/EU version uses sucrose i think, so that would explain the lower rating i guess.

[Rajala]

My bottle is in the fridge, but I measured at room temperature.

[Kerry Beal]

2 hours ago, Rajala said:

My bottle is in the fridge, but I measured at room temperature.

I keep mine in the fridge as well - it had warmed to room temperature by the time I tested it

 

[pastrygirl]

it was a long week in the Easter egg mines, but I'll find a Lindt bar and do some testing in a few days

 

no ketchup though 🤢🤣

[AAQuesada]

looking forward to seeing everyone's ketchup filled bonbon's with french fry inclusions! 😂🤣lol that's all I could think of reading this thread!

[Kerry Beal]

2 hours ago, pastrygirl said:

it was a long week in the Easter egg mines, but I'll find a Lindt bar and do some testing in a few days

 

no ketchup though 🤢🤣

I considered testing Miracle Whip - but thought that might cause even more of a divide.

[gfweb]

3 hours ago, AAQuesada said:

looking forward to seeing everyone's ketchup filled bonbon's with french fry inclusions! 😂🤣lol that's all I could think of reading this thread!

Thats a yinzer move. 

[pastrygirl]

On 3/20/2022 at 11:06 AM, Kerry Beal said:

So here's what I got - I didn't calibrate today - I had done so not that long ago.

 

Half as much water as chocolate - Aw 0.88 - Pro-Choc's estimate 0.96

one quarter as much water as chocolate - Aw 0.78 - Pro-Choc's estimate 0.87

 

 

I got the Lindt 70% & tested (at 20.6C for 4 min)

 

4:1 choc:H20 = 0.788 ... very firm though, wouldn't want it in a bonbon.  But a similar aW with added butter fat would be softer, right?

 

2:1 = 0.946

 

 

[Kerry Beal]

56 minutes ago, pastrygirl said:

 

I got the Lindt 70% & tested (at 20.6C for 4 min)

 

4:1 choc:H20 = 0.788 ... very firm though, wouldn't want it in a bonbon.  But a similar aW with added butter fat would be softer, right?

 

2:1 = 0.946

 

 

Interesting - we are kinda all over the place. 

 

I'd better retest my 2:1

 

 

[pastrygirl]

all over the place is right ... I tested the same samples today and got

 

4:1 = 0.818, 0.810, 0.814

2:1 = 0.911, 0.903, 0.906

 

I wonder what's up with the same samples testing differently.  Maybe I should actually read the instructions?

[Kerry Beal]

How long does each reading take?

 

 

[pastrygirl]

I did a couple at 4 minutes then one for 15

[Jim D.]

40 minutes ago, pastrygirl said:

all over the place is right ... I tested the same samples today and got

 

4:1 = 0.818, 0.810, 0.814

2:1 = 0.911, 0.903, 0.906

 

I wonder what's up with the same samples testing differently.  Maybe I should actually read the instructions?

 

Maybe I'm being too casual, but I would not find the variance in those readings disturbing at all.  I am interested in an estimate of shelf life, not in an exact reading of how much free water is in the sample, and the 4:1 readings are (rounded off) between 0.81 and 0.82, and the 2:1 ones are between 0.90 and 0.91.  My Pawkit readings are only to two decimals, so to me that would have been the same.  Aren't those close enough to estimate shelf life?  In both cases, of course, the readings are disturbing, but we are dealing with a water ganache here.  If you recall, when you were sending me fillings to test, the exact same sample would have slightly differing readings over a period of a couple of minutes. The software readings from Kerry, on the other hand, have a more significant variance.

[Rajala]

Hehe, if you read the instructions you can see that any machine have a repeatability range and a +- accuracy. So those combined will need to be taken into account while looking at repeated readings of the same sample.