I have been doing research on making a hard soda but I am never able to find anything that is able to completely describe the process, I have a bottle of orange extract that I would like to use.
Any fermentable sugar can be used to ferment. Sucrose, glucose, maltose, honey, corn syrup and cane sugar are all good examples. Molasses treacle and candi sugar are other more flavoured examples. Ultimately most ripe sweet fruits will ferment themselves - like grapes.
If you are trying to carbonate your drink then adding up to 10g of sugar to a 1 Litre bottle is about right for a good fizzy drink. Add less (eg 5-6g) for a less fizzy drink. If the juice being fermented has a higher concentration of sugars then one can dilute the juice or watch the progress of fermenting very carefully and drink before the bottle gets too pressurised. Many shop brought juices have around 100g of sugar per litre of juice. So they would be problematic to ferment without lots of timely attention. Supermarket apple juice will (for example) make good and quite alcoholic cider. Sweeter juices could be diluted but that may detract from the strength of the flavour. Its a catch22 situation. I have used about 75ml of lemon juice in 1L of water/10g sugar. It makes cloudy lemonade. Very nice and economic.
If you use fruit purees or concentrates then the base fizzy liquid is made up as above and the fruit flavouring added to about 10% or so by volume. Some very (artificial) flavoured concentrates just need a good squirt into the bottle. Again watch the sugar content and adjust your ferment as needed.
In general sodas will carbonate well in 3 days or so. A week is more than enough if the soda is kept in a warm (room temperature) place. 18-20C is a good range but fermentation can go on up to (say) 35C or as low as 5C (but it will take much longer to complete). Once carbonated it can help to store the bottle in a fridge.
The main problem with making sodas is the sweetness. If one uses sugar to sweeten then the sugar can also ferment away. This means the flavour changes over time and is optimal during a period of a few days only. This is normally handled by drinking the soda when ready and not storing "old stock". It can also be handled by adding a non-fermenting sweetener like Stevia - it's organic and not a "chemical" like many artificial sweeteners.
I would tend to use champagne yeast for a cleaner flavour but to be honest for strongly flavoured sodas almost any yeast (including baking yeast) will do.
I would STRONGLY recommend the use of 1L PET fizzy drinks bottles and not glass bottles. Plastic bottles can be squeezed to check the pressure and if all goes wrong they produce next to no dangerous "glass shrapnel". Bottle bombs are a bad thing.
And if soda is what is wanted I should recommend the use of "Real Ginger Beer plant" instead of just yeast.Or water kefir (tibicos). All of these are a SCOBY (!?!) and are just great for making ginger beer and many similar flavoured drinks on a continuous production basis using a 5L demijohn. You may be able to find a supplier near you can can sell you some starter grains.
Soda is simply water, sugar, yeast, and flavouring (artificial or natural). The above directions are helpful.
I have made a couple of batches of hard ginger ale, and will be experimenting with various flavourings with my current batches. I will be trying strawberry kiwi, raspberry, and mint. There are multiple recipes for the hard ginger ale online. The fruits/mint will be added a week or so before the secondary fermentation will be complete, and then strained out before bottling.
Just experiment - that's what I'm doing!
