Water activity and ganache shelf life?

[jrshaul]

A friend of mine is starting a bakery, and I'm helping hi with ganaches and pralines. Neither of us is very keen on the use of sorbitol, glycerin, and other purely hygroscopic ingredients, but I can't see another way to keep the aW at a sub-7 level.

Is there a chart somewhere documenting the self life reduction for higher aW? And how large is the advantage of blending under vacuum?

[Edward J]

Yeah, Wybauw's #2 and #3 talk a lot about it, good information.

That being said, I thik you're looking for the holy grail

Here's why:

You can increase shelf life with the use of sorbitol, etc. However, as the product ages, the flavours will change--think wine, beer cheese, etc. However, the flavours in ganache won't change for the better.

What I do is have about 25% of my product line made up of fresh cream ganaches. You can successfully vacuum pack and freeze finished bon-bons, and you can freeze hand rolled truffle centers--dipping and finishing as needed.

There are a lot of other shelf stable products--nuts, giandujas, pate de fruits, nougats, etc.

[jrshaul]

I just received Wybauw's #2, and am starting #3 tomorrow.

I may have badly underestimated the shelf life of chocolates. I've read that a .85 will result three months, not three weeks. I can do 0.8 very neatly.

Is there a service that will test the aW of samples economically? Meters are often over $3,000, but there's not likely to be much variation.

[Edward J]

In one ear and out the other...........

Not only will flavours change, but fillings will shrink, and shell walls will cave in slightly

[jrshaul]

In one ear and out the other...........

The question is not one of convenience or profit, but simple safety. The cost of retail venues mean that most locally produced chocolate is sold through independent retailers; however, the required certification is difficult to obtain. I'm not a professional, so I prefer to err heavily on the side of not making anyone sick; I recently had a bad shock when some truffles went fungal, and prefer to plan for the worst case scenario.

Outside of a freezer, I wouldn't dream of selling to anyone outside of seven days. They just don't taste right. But there's always going to be some doofus who expects fresh food to still be safe after eight weeks of 80F heat.

[Edward J]

Fair enough, that is a good reason for wanting long shelf life.

Most "artisanal" chocolate makers avoid the above described nightmare by having some kind of a caveat on their packaging which includes a "best before" date as well as verbally informing the customer to enjoy within a week.

The cost of adding all of the "wierd sugars" is as follows:

-Recipie must be perfectly balanced

-Humidity and temp must be still be controlled

-Product may still "go fungal" if not perfectly sealed, or exposed to any contaminents. (including air borne yeasts) You will need a minimum of 3 hours for ganache to set before capping off.

-Health dept may or may not require you to inform customers that your product contains sorbitol and/or glycerol.

-"Wierd sugars" such as sorbitol, glycercol, etc are polyols. Consumption of 20-30 grs may result in a, uhh..(ahem) "laxative" effect. You may or may not be required to inform your customers of this side effect.

-Bragging rights of "all natural" ingredients is off.

[jrshaul]

I am hoping to turn the problem from a culinary problem to a distribution problem by the methods you suggest. Shipping the product shrinkwrapped and frozen so it may be defrosted immediately before purchase may also help.

Back to the original problem: does adding alcohol reduce Aw or is it considered seperately? I do like brandy in my ganache.

[Kerry Beal]

I am hoping to turn the problem from a culinary problem to a distribution problem by the methods you suggest. Shipping the product shrinkwrapped and frozen so it may be defrosted immediately before purchase may also help.

Back to the original problem: does adding alcohol reduce Aw or is it considered seperately? I do like brandy in my ganache.

Alcohol improves the shelf life but is not reflected in the aW reading.

[Chocolot]

I think you have to have a very high amount of alcohol in there to act as a preservative--so much so that you can't legally sell it in most states. Think I read that in Wybauw.

[Kerry Beal]

Something like 18% of the water as pure alcohol as I recall. Legal here!!! Palatable is another question. I recall making one of the centers from Geerts - by the time I was done my taste tests I was darn near totally pissed.

[Edward J]

O.K., according to Grewling, (and I've done it myself often) freezing truffles is as follows:

-Vacuum pack (best done with a stable cardboard or plastic base)

-Refrigerate 24 hrs

-Freeze

To serve:

-Place in fridge with unbroken packaging for 24 hrs

-Place at room temp for 24 hrs before opening packaging

All this is to prevent condensation on the product.

Shelf life clock starts ticking once it's out of the freezer

Bonuses of this system are obvious, as well as the fact that most retailers won't demand ISO 2000 standards for frozen product.

Cons are as follows:

-Expense of vacuum packaging (including labour)

-John Q public most likely won't follow the specific thawing instructions, and will get condensation on product. Once the condensation dries off you get sugar bloom and John Q will scream "There's white mold growing on my chocolates!"

If you go this route with consumer product you have to have the caveats printed very clearly on the packaging. But the system itself works very, very well.

[gap]

Just to add to Edward J's comments - I do this freezing/unfreezing process a LOT and have never had a problem. I do not vacuum pack my chocolates. I put in a cheap tupperware container ($2 box holds 70 truffles) and wrap in a few layers of clingwrap/gladwrap/plasticwrap. Otherwise follow exactly the same process.

[jrshaul]

Just to add to Edward J's comments - I do this freezing/unfreezing process a LOT and have never had a problem. I do not vacuum pack my chocolates. I put in a cheap tupperware container ($2 box holds 70 truffles) and wrap in a few layers of clingwrap/gladwrap/plasticwrap. Otherwise follow exactly the same process.

This is very good news.

My distribution plan is as follows:

1. All chocolate is to be frozen during production. During the summer, refrigeration is required in transport. May as well make 'em frozen.

2. Vacuum-packing is ideal, but for only a few weeks, I'm hoping that shrink-wrapping is adequate to prevent humidity from entering upon defrosting.

3. The individually vacuum-packed boxes may be shrink-wrapped into bundles.

4. The retailer takes the frozen bundles from the freezer and defrosts them overnight before opening the shrink-wrap on the bundle.

5. The boxes of chocolates are sold at room temperature.

The only real thing I've got going for me is cost - I'm hoping to have 1/3 lb boxes for $8 each, which puts me in the price range of traditional grocery stores. I feel quite the doofus discussing this with seasoned professionals, but I have also been very fairly careful in my cost analysis and run all this past an experienced bakery owner.

[Edward J]

Now what did I say about ears?????

You HAVE to defrost in the fridge 24 hours, THEN at room temp for 24 hrs BEFORE opening up the vacuum pouch.

Failure to do so will result in condensation forming on the shells.

By all means, go ahead and experiment, you'll come to the same conclusion as Mr. Grewling.......

[jrshaul]

Now what did I say about ears?????

"Overnight" is in this case a malapropism for the slow process you suggested. I'm more concerned about retailers willing or able to perform it properly. The shrink-wrap will be left on the individual box until purchase. It's not especially complicated, but the potential for damage is worrisome.

As vocal as I am vis a vis tipping, I do respect your superior experience.

In lieu of the fridge stage, I will test to see if a styrofoam container delays the defrosting process. A large, heavily insulated carton full of many pounds of chocolates would defrost very gradually - potentially even slower than it might within a fridge. Styrofoam may be necessary to prevent damage in shipping, so using a larger quantity is no hardship.

I'm more concerned about the shrink wrapping being suitable to prevent humidity from entering - if anyone could speak to it versus vacuum packing, I'd appreciate it. In theory, it's seamless. In reality? I don't know. If multiple boxes could be combined and vacuum-packed, it would reduce the cost. There may be disposable tupperware analogues that are within the price range.

I have a data logger I can borrow from the shop to test my theories. I'll put a bare thermocouple right in a truffle before the 48-hour procedure, and should have a very accurate measure of the rate of defrosting. If the rate of warming in the styrofoam is less than that of the fridge, I will consider it an acceptable substitute.

Edited January 14, 2013 by jrshaul (log)