Water Activity/Shelf LIfe

[Jim D.]

1 hour ago, Rajala said:

I've been experimenting for some time with a "brownie" bonbon filling (the only trace of chocolate is in form of cocoa powder), that contains flour. Is there anyone with experience in terms of using flour in fillings and what to think about in terms of food safety? Is it considered safe as long as you keep an eye on everything as usual? I mean, there are baked goods that lasts for month, although with a lot of preservatives in them.

 

The AW of the filling is 0.6229 - so on its own, it's pretty low.

 

The brownie idea sounds interesting.  I don't think there should be an issue with using flour.  If there is one, there are certainly a lot of chocolatiers using some form of cookies in their bonbons who would be in trouble.   In fact, there is one of them located just down the street from you (more or less), Kalle Jungstedt, who uses cookie layers a lot.  Of his tiramisù's savoiardi layer, he writes:  "the cookie base is water free with months of shelf life."

[Rajala]

27 minutes ago, Jim D. said:

 

The brownie idea sounds interesting.  I don't think there should be an issue with using flour.  If there is one, there are certainly a lot of chocolatiers using some form of cookies in their bonbons who would be in trouble.   In fact, there is one of them located just down the street from you (more or less), Kalle Jungstedt, who uses cookie layers a lot.  Of his tiramisù's savoiardi layer, he writes:  "the cookie base is water free with months of shelf life."

 

Yeah, I hear you. I've made those pipeable crunch layer for years, but they're basically moisture free. This filling is sugars, water, and fat in one. But maybe I'm just overthinking things here.

[pastrygirl]

3 hours ago, Rajala said:

I've been experimenting for some time with a "brownie" bonbon filling (the only trace of chocolate is in form of cocoa powder), that contains flour. Is there anyone with experience in terms of using flour in fillings and what to think about in terms of food safety? Is it considered safe as long as you keep an eye on everything as usual? I mean, there are baked goods that lasts for month, although with a lot of preservatives in them.

 

The AW of the filling is 0.6229 - so on its own, it's pretty low.

 

Isn't below 0.65 'microbially stable' i.e. nothing grows?  I wouldn't worry, especially if the flour has been cooked.

[Rajala]

2 minutes ago, pastrygirl said:

I wouldn't worry, especially if the flour has been cooked.

 

It's only heated a bit. But in the next test run, I'm going to roast the flour - thinking it will give off a better flavor.

[Jim D.]

38 minutes ago, Rajala said:

 

It's only heated a bit. But in the next test run, I'm going to roast the flour - thinking it will give off a better flavor.

 

I was going to say that if you are using raw flour, there is the issue of taste.  I assume the filling is sticking together with butter or something similar?  There might be the issue of having a filling that is too dry, taste-wise, and there is the consideration that ganaches dry out as they sit.  But if this turns out as well as your cinnamon bun recipe (which I use frequently), then I will have to beg for the recipe.

[Kerry Beal]

5 hours ago, Rajala said:

I've been experimenting for some time with a "brownie" bonbon filling (the only trace of chocolate is in form of cocoa powder), that contains flour. Is there anyone with experience in terms of using flour in fillings and what to think about in terms of food safety? Is it considered safe as long as you keep an eye on everything as usual? I mean, there are baked goods that lasts for month, although with a lot of preservatives in them.

 

The AW of the filling is 0.6229 - so on its own, it's pretty low.

Should last for a lot of months at that value. 

[Rajala]

11 hours ago, Jim D. said:

 

I was going to say that if you are using raw flour, there is the issue of taste.  I assume the filling is sticking together with butter or something similar?  There might be the issue of having a filling that is too dry, taste-wise, and there is the consideration that ganaches dry out as they sit.  But if this turns out as well as your cinnamon bun recipe (which I use frequently), then I will have to beg for the recipe.

 

Hehe, I've started to share all my recipes. What's the use if they're just in my notes forever?

 

10 hours ago, Kerry Beal said:

Should last for a lot of months at that value. 

 

Yeah. I read something about flour and microorganisms. But it was out of context in terms of bonbons. So maybe it was just the regular "you need to think about x and y when it comes to shelf life".

[GRiker]

I purchased an aw meter off Aliexpress and it arrived yesterday.  Today I used it for the first time.  I used it on my first attempt of Pate de Fruit.  The PDF was a learning experience but I decided I could use it to test the aW meter.

 

I did a 3 different samples and got the following measurements:

 

Sample 1 PDF

5 minutes 0.77

10 minutes 0.74

15 minutes 0.72

20 minutes 0.70 

didn't change after that 

 

Sample 2 PDF

also settles at 0.70

 

Sample 3, simply Heinz ketchup

10 minutes 0.81

15 minutes 0.86

20 minutes 0.88

settled 0.89

 

So here's my questions.  Is it the last measurement that is the "real" measurement?  Should I plan on waiting 20 minutes to get my accurate measurement?  Feeling a little out of my depth here!

 

[Kerry Beal]

4 hours ago, GRiker said:

I purchased an aw meter off Aliexpress and it arrived yesterday.  Today I used it for the first time.  I used it on my first attempt of Pate de Fruit.  The PDF was a learning experience but I decided I could use it to test the aW meter.

 

I did a 3 different samples and got the following measurements:

 

Sample 1 PDF

5 minutes 0.77

10 minutes 0.74

15 minutes 0.72

20 minutes 0.70 

didn't change after that 

 

Sample 2 PDF

also settles at 0.70

 

Sample 3, simply Heinz ketchup

10 minutes 0.81

15 minutes 0.86

20 minutes 0.88

settled 0.89

 

So here's my questions.  Is it the last measurement that is the "real" measurement?  Should I plan on waiting 20 minutes to get my accurate measurement?  Feeling a little out of my depth here!

 

These are different readings on the same sample?

[Jim D.]

6 hours ago, GRiker said:

I purchased an aw meter off Aliexpress and it arrived yesterday.  Today I used it for the first time.  I used it on my first attempt of Pate de Fruit.  The PDF was a learning experience but I decided I could use it to test the aW meter.

 

I did a 3 different samples and got the following measurements:

 

Sample 1 PDF

5 minutes 0.77

10 minutes 0.74

15 minutes 0.72

20 minutes 0.70 

didn't change after that 

 

Sample 2 PDF

also settles at 0.70

 

Sample 3, simply Heinz ketchup

10 minutes 0.81

15 minutes 0.86

20 minutes 0.88

settled 0.89

 

So here's my questions.  Is it the last measurement that is the "real" measurement?  Should I plan on waiting 20 minutes to get my accurate measurement?  Feeling a little out of my depth here!

 

 

If it's helpful, I did a similar experiment (see post of August 4, 2021, in this thread).  It showed that the Aw of a sample goes down as the sample sits--but only if you measure the top of the sample, not if you stir it between measurements.  In the latter case, the Aw remains unchanged.

[GRiker]

12 hours ago, Kerry Beal said:

These are different readings on the same sample?

I had three different samples.  All the readings under the heading Sample 1 are from the same sample.  Sample 2, I only have the one settled measurement.  Four different data points from the same Sample 3. 

[GRiker]

10 hours ago, Jim D. said:

It showed that the Aw of a sample goes down as the sample sits--but only if you measure the top of the sample, not if you stir it between measurements.  In the latter case, the Aw remains unchanged.

Thanks for pointing that experiment out.  I did read through that.  I'm only holding for 20 minutes.  Your equipment is many times more expensive that what I'm using, so not sure if I can compare it, but ... when you press the measure button is it an instantaneous measurement? or does it move around and eventually settle?

 

I guess it would be helpful for me to get some standards...

[pastrygirl]

@GRiker I don't think it's supposed to be instantaneous.  I have the Rotronic, which lets you set a 'dwell time' of how long you want it to analyze the sample before computing.  20 minutes might be what you need for accuracy.

[GRiker]

Thanks @pastrygirl.  That does make some sense to me.  The scant instructions that come with it do say some samples require 20 minutes of settling.  I think I will get some pure nacl so I can make a standard.  Might give me a little more confidence in the meter.  

 

Would you mind posting which Rototronic you have? 

[GRiker]

On 4/12/2022 at 4:27 PM, Kerry Beal said:

I should have checked distilled water on both but I'm not sure I have any here. 

 

Making your own 6 mol NaCl solution - 100g pure NaCl, add into 200g hot distilled water, stir it. Cool to room temperature. 2. Keep the solution into a brown bottle for one week at room temperature. The solution AW value should be 0.75~0.77

@Kerry Beal If you did have distilled water, would you you have expected a value of 1.0?

 

For making your own NaCl solution are you saying that one week in a brown bottle is the shelf life? You could use it as soon as it's at room temperature.  Is that correct?

 

When you used your aliexpress meter, do you remember how long you waited to get the measurement? 

 

[pastrygirl]

Hygropalm 23

[Jim D.]

54 minutes ago, GRiker said:

Thanks for pointing that experiment out.  I did read through that.  I'm only holding for 20 minutes.  Your equipment is many times more expensive that what I'm using, so not sure if I can compare it, but ... when you press the measure button is it an instantaneous measurement? or does it move around and eventually settle?

 

 

The Pawkit that I have does not give an instantaneous measurement.  It determines the amount of time needed (and this varies with samples).  It can take anywhere between approximately 5 and 15 minutes.

[ChristianD]

I have calculated how high the aw value should be based on the ingredients of Heinz ketchup. This is at least the settled value of 0.89. I used the European recipe as a basis, which contains sugar instead of high-fructose corn syrup. This shows that the basic rule that the aw-value goes down as the sample sits is not applicable, at least not here. It seems that your device is not able to create uniform measuring conditions (temperature and humidity). Higher quality devices are capable of this. For example, any change in temperature has an influence on the aw value. If the ketchup comes out of the fridge, the aw value is initially lower. If the temperature of the sample rises, the aw value will also be higher.

[Kerry Beal]

2 hours ago, GRiker said:

@Kerry Beal If you did have distilled water, would you you have expected a value of 1.0?

 

For making your own NaCl solution are you saying that one week in a brown bottle is the shelf life? You could use it as soon as it's at room temperature.  Is that correct?

 

When you used your aliexpress meter, do you remember how long you waited to get the measurement? 

 

Been a while - but yes I believe you can measure once it's at room temperature.