February 13, 2006
Now having a dilema? have been experimenting with extending the shelf life naturally and not with any chemicals and have been told that if l use evaporated milk instead of fresh cream this will extend the shelf life to 3- 6 months. Has anybody tried using this method? If so does it taste sweeter? and does it realy extend the shelf life?
March 20, 2006
I've not tried using evaporated milk to make a ganache. I suspect that once opened evaporated milk will spoil as quickly as cream.
Do a simple experiment. Take four sterilized cups, half-fill one with fresh cream from the fridge. Half-fill the second with fresh cream brought to the boil. Half-fill the third with fresh cream 'home' pasteurized, ie raised to 72° C for 16 seconds. Finally, half-fill the fourth with evaporated milk. Leave in a warm room and check twice a day, tasting each until you think it unwise to taste anymore.
Shelf-life is dependant on: 1) the bacteria and spores introduced into your confections from the ingredients (particularly cream), air, hands, utensiles; and 2) the 'water activity' of you final preparation. Water activity in turn is dependant on i) moisture, ii) binding of that moisture (ie by sugars, sugar alcohols), iii) temperature.
Better to bind as much of the water in your ganache as possible. You can do this by: a) adding sucrose b) by adding glucose, fructose or invert sugar c) by adding sorbitol d) by inverting the constituent sucrose of your chocolate. Which will taste sweeter? - d) will produce a less sweet ganache than c) which will produce as less sweet ganache than b) which will produce a less sweet ganache than a) for the same moisture and water activity.
From my experience, to achieve a 3-6 month shelf life for a ganache you will need to either reduce the moisture to too low a level or reduce the storage temperature to near zero or below.
February 13, 2006
Thank you, will try that tonight
l was told that using 'invertin' or 'sorbitol' justs keeps the ganache at a stable consistany and doesn't dry out rather than extend the shelf life?
March 20, 2006
Sorbitol is a sugar alcohol. It binds some of the free water within a ganache making it unavailable for bacterial / spore growth. Sorbitol binds more water (reduces water activity) by a greater degree than sucrose or invert sugar (fructose/glucose). However sorbitol does have a cooling and laxative effect.
Invertase (Invertin) is an enzyme which breaks sucrose into equal amounts of fructose and glucose, just as the enzymes in our guts do to a chocolate once eaten. Invert sugar (fructose/glucose) again binds free water to a greater extent than sucrose. You can add invertin to a ganache (1 ml invertin per 1 kg of sucrose = 1 ml invertin per circa 6 kg ganache). Alternatively you can convert the constituent sugars of a couverture before making a ganache.
Both also retard crystalisation and maintain a moist ganache.
Invertin is regarded as an ingredient and not an additive under UK (and US/EU?) law.
http://www.keylink.org supply both sorbitol and invertin (in manageable quantities).
Sorry for those from egullet who already read this! In Wybauw's book- Fine Chocolates- I think page 110 there is a recipe for Araba. It calls for sorbitol and pistachio compound.
Now I want to use invert or glucose or better yet nothing - instead of sorbitol- canit be done? Is there a conversion?
Also, I don't want to use compound (not natural) - but real paste- any ideas on how to adjust the recipe? Or as usual, I will make my own adjustments and do trial and error- which I am tired of!