this will eventually develop into a comprehensive post but for the moment i will just start to organize my ideas and recipes…
i think i want to tackle a recipe for extra brut hibiscus soda as a new cocktail acid… and a yeast carbonated tonic water…
amerine’s “technology of wine making” outlines the two most important things to consider in soda making… the ideal PH of a champagne is 3-3.2 and you should plan on fermenting to dryness and only sugar in your dosage after disgorging your yeasts… this advice runs counter to any of the amateur guides on soda making. most guides say sugar to taste and manuelly stop fermentation by putting the soda into the fridge… this introduces a slew of variables that you can never change and your product will be all over the map, not to mention the risk of explosions and bottles that gush everywhere…
this does limit your options to avoiding things with too much built in sugar…
sugaring.
“the pressure desired in sparkling wines at the end of the closed fermentation is about 5 to 6 atm at 10 degree celsius (50F); that is, about 75 to 90lb pressure per square inch. for each atmosphere of pressure approximately 0.4% of sugar (4g/liter) is required. thus to produce 6 atm pressure would require 6 * 0.4 or 2.4%, or 24g/liter sugar, or about 20lb / 100 gal. of wine.”
amerine does note that about 1 gram does not ferment and it needs to be accounted for.
“brut” test batch for two champagne bottles…
1.5 liters with 25 grams per liter of sugar. this reads as 2.25 brix with a hand held refractometer. i didn’t pay much attention to sanitation because it is only a test. 750ml in a classic champagne bottle seems to leave three inches of bottle neck unfilled… the yeast used was a fraction of a “cooper’s brewing yeast” that i think is a beer lager yeast.
one thing to note is that conversion tables put 25g/l of sugar at over 2.25 brix. it is actually closer to three. so i wonder if i have a temperature or calibration problem. there seems to be a few ways to calculate potential alcohol but none of the ways estimate it over 2%.
“brut” test batch 2 for four bottles with flavoring and acidity
3 liters with 25 grams per liter of sugar. one random sized pack of “chai spice” that was a sample and some added malic acid to bring the PH down to 2.4 plus the rest of the coopers brewing yeast…
after fermenting for quite a few days, i drank the first test from a warm bottle and was not impressed by the carbonization. i chilled down test 2 in the fridge and found its bubbles quite comparable to champagne. one thing that you notice is that disgorging is really important. the floating sediment is quite unattractive. another thing to note is that the dry zero dosage structure is kind of awesome… you could add a sugar dosage but because the alcohol level is so low it may need a preservative to prevent the soda from further fermenting… i personally really enjoy this bone dryness and champagne acidity… from the chai soda i seemed to notice the flavor of apples…
disgorging.
getting the yeast out probably is the hardest part of the soda making process and maybe the most time consuming. so far my technique has been to add slightly too much sugar so i get enough pressure that the bottle slightly over flows upon uncapping (hopefully i can follow up with an exact number of extra grams). if the bottles are fermented and riddled downward then only turned upwards just before uncapping for disgorgement, nearly all the yeast will be collected in the neck. quite a lot will be stuck under the cap and hopefully the rest will nearly glue itself to the sides of the neck. when its done over flowing the neck can be swabbed out. freezing the neck into a plug is the classic and most thorough way of disgorging but my understanding is that you still need to swab the neck and its probably not worth the massive amount of prep unless your going to spend eight hours disgorging and get a decent amount of money for your product…
dosaging.
i can’t say i’ve mastered dosaging. so far i’ve just been adding the still tea to refill the bottles all while everything is as cold as possible. you could add more sugar and augment the structure of the drink but i haven’t been tempted.
reseal.
after recapping short term aging like a beer will decrease some of the yeasty aromas created during fermentation. some yeast produce less bread like aroma than others. beer brewers like sierra nevada use “clean fermenting” yeast strains which might be worth experimenting with.