Following its expedited launch during the V'Ger incident, the warp core of the refitted USS Enterprise required new fuel equations to balance the intermix. The essential simulation of the flow sensors was bypassed resulting in an antimatter imbalance. (Star Trek: The Motion Picture)
- "The matter and antimatter tanks on a Galaxy-class starship are nine-tenths depleted. Calculate the intermix ratio necessary to reach a starbase 100 light years away at warp factor 8."
In the same year, after the Shuttlecraft 13 crashed on Vagra II, the USS Enterprise-D was rushed to have warp drive operational. In the start-up sequence, prior to powering up the engine core and injecting reactants, the matter-antimatter injectors were primed to a ratio of 25:1. Minimal warp speeds were recommended, however Captain Jean-Luc Picard ordered warp 8. (TNG: "Skin of Evil")
Several aspects of the intermix ratio are further explained in the Star Trek: The Next Generation Technical Manual (pages 61-62). According to the text, the 1:1 ratio applies when traveling at warp 8 or faster. When traveling at lower speeds the intermix ratio is different - a ratio of 25:1 is only used when the core is online in an idle state, prior to full startup. At warp 1 it is tuned to 10:1, gradually changing until it reaches 1:1 at warp 8.