1. Six hour old lemon juice wins!
2. 1-3 day old vacuum-sealed lemon juice is passable, though never quite as voluptuous as the six hour fresh juice. Even the vacuum sealed four day juice was alright and comparable to pre-24hr fresh juice, but it was beginning to go bad.
3. If you squeeze lemon juice at your bar at 3pm every day, then your lemon juice will be usable from that moment until (maybe) the beginning of service the next day, and it will peak around 9pm-12am that night. If you squeeze lemon juice at 3pm every three days then strain and vacuum seal it in glass bottles with Vacu Vin wine stoppers, upon opening those bottles right up to three days, you'll always have quite usable and pleasant lemon juice, and you'll be able to juice/waste way less.
4. The acidity level of fresh and desirable lemon juice hovers around 2.79ph, and as it begins to near the 15/21-hour mark, it drops to around 2.73/2.75ph. Every vacuum sealed juice over 72 hours old showed the same and worse degradation, and the flavor degradation followed in turn.
FINAL: By vacuum sealing fresh lemon juice, you never get the few hour window where the lemon juice is delightful, but you avoid the high amplitude moodiness illustrated by the flavor changes along the road of the first 24 hours. The point of this experiment was to find out how little we can reasonably get away with juicing, or how long we can get away with saving fresh juice-- but in this case, it seems that for consistently pleasant lemon juice all the time, one would have to only ever use vacuum sealed lemon juice between the ages of 24 and 72 hours! Strange.
-I purchased a case of lemons and kept them all in my home refrigerator at a constant temperature.
-Each day at 3pm for seven days straight, I juiced enough lemon juice into a quart container such that post-straining through a Cocktail Kingdom Coco Strainer it weighed 150g on a gram scale. I funneled these daily portions into brand new, washed 187ml champagne splits and Vacu Vin sealed them. I labeled them with the date, and put them in my refrigerator-- knowing that they'd been squeezed at 3pm each day.
-On the seventh day of this, after the ritual 3pm juicing, I began to juice the same 150g every 3 hours until 3pm on the eighth day. I woke for each of my alarms, shockingly.
-At 3pm on the eighth day, I invited three industry friends over and we tasted through everything together and took notes.