I think that trying some room-temp preparation and cold extraction techniques to preserve and incorporate the tasty volatile compounds/organic acids/etc into a suspension/emulsion concentrate will serve you well.
This is done by harnessing the power of the "salting-out" effect to help create a more potent water-loving-compound-extraction, followed by a more lipophilic treatment to round up the rest of the flavor compounds, finished with a stabilizer/emulsifier for shelf life and rancidity control.
I am suggesting a suspension/emulsion because, only some of the ginger's flavor compounds are water-loving and we want to be able to spread them all out fairly evenly in the end product. You will either wind up with something like a salad dressing emulsion that separates, but will reincorporate if shaken, or a thick gel suspension for dilution. To design this emulsion, let's take a different approach to some of the steps that BobMcGee outlined.
Here's what I was thinking:
First, freeze your ginger. Once the root is frozen, peel it(yes, a regular vegetable peeler works, BE CAREFUL THOUGH!), and then grate using a fine microplane grater. You will end up with a pulpy-ginger-mash with very few long ginger "hairs".
Freezing the ginger helps disrupt the cell walls of the rhizome(water in the cells expanding upon freezing), and will slow down native enzymes inside the ginger. Also, grating frozen ginger(for me) seems to go faster than grating raw ones, and there are fewer of the hairs to deal with when you're finished grating. This helps me get the very smallest ginger pieces possible, since I don't have a vitamix. :-(
Combine lengthening extraction time with reducing ginger water by allowing excess water to evaporate in the fridge or on your kitchen counter-top rather than heating. Some of the flavor molecules in ginger will change when exposed to temperatures greater than 50F, thus changing the flavor. Not that warmed ginger isn't also good, but not heating the solution leaves flavor options for you to explore later, rather than being stuck with only cooked ginger flavor. You are realistically going to need to do at least one water extraction and one oil/alcohol/fat extraction to get the majority of the ginger flavors. Increasing the holding time for both extractions is key, so be lazy...let them sit at least overnight. Below is a process I use.
Two-phase extraction example:
- Water extraction
20g of frozen ginger, peeled then grated into a pulpy-mash
2g CaCl dissolved in water
These are combined in a glass jar with a cheesecloth top that is placed in the refrigerator(at least overnight).
(You can either use invertase to cleave the sucrose in the ginger into glucose and fructose thereby utilizing the salting-out effect, or use calcium chloride to help drive the volatile compounds out into the aqueous phase. If you use invertase, allow the water and ginger solution to sit on the counter, not in the fridge)
When you're ready for the oil extraction, filter and reserve the aqueous ginger solution in a separate container, you will need it later.
- Alcohol/Oil Extraction
Ginger-mass leftover from the previous step
100mL 40 proof alcohol (you could use a higher proof, but I use the lower proof because there is a little water left in the ginger mass from the previous step) Personal preference is to use mescal(mezcal?) or a bit of nice brandy/congac.
The alcohol and ginger slurry I allow to sit in the fridge covered with cheesecloth for a while...at least overnight. I tend to forget about this for a week and then find it again when I'm rearranging the fridge. The longer I let the alcohol and water evaporate, the more fiery it becomes.
I blend the two constituents with an immersion blender, cover with cheesecloth and then let the solution sit overnight in the fridge. I have in the past used a neutral oil(canola & grapeseed), but I needed to let it sit in the fridge for more than a week to get more flavor out of the root.
Here's where the concentrate/emulsion making occurs:
I use xanthan gum and lecithin to get the right concentrate consistency, and to slow release of the volatile compounds. I also like xanthan because it is a thermoreversible gel if memory serves right. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3866759/ http://pubs.acs.org/doi/abs/10.1021/jf048111v http://www.sciencedirect.com/science/article/pii/S0308814607009624
Add some xanthan gum to aqueous solution(in these proportions I used 2.3g) This will help prevent the loss of the volatile compounds to the air as it is stored. The result is a bubbly light-yellow goo. Slowly incorporate the oil/alcohol solution with 1/4 tsp of lecithin(again, I use the immersion blender to do this) then finish with salt (punches up the flavor). To control rancidity I would either add alpha-tocopherol(vitamin E) or turmeric to take care of free radicals that may occur during longer-term storage.
All said and done, this is a slower process because it requires evaporation at cold temperatures. This method does however allow you to make a "concentrate" or extraction without adding sugar, or using heat...if that matters. I do it this way because it allows me to be lazy,(I leave this in the fridge covered with cheesecloth for more than a week getting rid of the water sometimes.) and it means I don't have to worry about cleaning up melted sugar from a saucepan later!