The word "tutti" in music has come to mean two different things:
It can mean all voices or instruments performing together, or it can mean a passage or section of music meant for all performers.
The first known use of the term in the former sense was in 1724, and in the latter sense in 1816.
In the former sense the entire forces of the grand symphony orchestra comes to mind, which translates for the organist into the "full organ" at its absolute strength.
Because controlling the organ involves the ability to bring on or cancel the full organ as quickly as possible, most consoles being built today are supplied with a reversible thumb piston engraved with the word "Tutti" or perhaps only with a "T," which is typically placed on the far right below one of the manuals (photo); this control is commonly duplicated by a toe stud made playable by the right foot to allow the full organ to be engaged or retired when both hands and left foot must be occupied on the keys; this piston and toe stud are typically "reversible" in that the first push turns them on, and the second push turns them off.
In some instruments the first toe stud in the first row to the right of the crescendo shoe duplicates the "Sequencer Forward" piston which moves forward through the general combinations, one-at-a-time, with each push; this is an extremely useful control to have but NOT to be confused with the reversible Tutti piston which brings on the fullest sound all at once with the first push and retires it with the second push.
When a so-called "Seq +" toe stud like this is supplied, another "Seq -" toe stud will be supplied on the opposite side, first row to the immediate left of the swell shoes which duplicates the "Sequencer Backward" piston and moves backward through the general combinations, one-at-a-time, with each push.
Depending upon how the generals combos are programmed the Seq + toe stud might be used exclusively by the right toe to add or retire stops during the course of a piece, and, with practice, the right toe could be easily trained to always find this one same toe stud during the performance of the piece without looking down.
A moment's thought will show that any control which can bring on the fullest possible sound with the touch of a single button makes the most jarring effect the organ can produce and must therefore be used very carefully, thoughtfully, sparingly, with deliberate intention, and be kept in reserve for final, climactic or other special places in certain music.
Organists and builders are not always in agreement about which sound colors and pitches of stops should enter into this Tutti; for this reason the Tutti piston has been made programmable in many instruments so that different organists can adjust it to suit the music and their own personal taste.
In other instruments where the builder has made the Tutti non-programmable, the factory decides and pre-sets this combination in advance, once and for all, and it cannot be changed.
When the music calls for the full organ, this DOES NOT mean "pulling out ALL the stops."
The biggest problem electronic digi organ manufacturers face is what can be done for what price; this market has always been competitive, and manufacturers experience periodic lulls in sales; generally speaking, in the market for these instruments, manufacturers find that buyers are interested in more stops, more manuals, more controls, etc., than the very finest musical product.
This encourages manufacturers to place a less expensive non-programmable Tutti and Crescendo (whose full position duplicates the Tutti) in their products to allow them to be marketed as still "having one."
Unfortunately, in a non-programmable Tutti, EVERY speaking stop in the organ at all pitches, and every sub and super coupler, intermanual coupler, and manual to pedal coupler save for celestes, percussions, and tremulants is generally wired "on" by the factory; this means ALL stops of delicate intonation, large scale, tubby-sounding diapasons and flutes, imitative strings, color reeds, big reeds, the Vox Humana whose characteristic voice depends upon the tremulant, mixtures, and mutations -- at ALL pitches.
Nowadays just about all Tutti and Crescendo controls in new digi organs are programmable, but organists may still encounter older digi instruments from time to time in which they find non-programmable features which have them tied to a thick, opaque, and muddy-sounding full organ Tutti and full Crescendo.
The only logical reason for making these features non-programmable in an organ is cost savings, as they have nothing to recommend them otherwise; organists, when they find them, will only use them when nothing else will do, and then only grudgingly.
The great art in building up choruses to the full organ summit is in deciding what NOT to include in that buildup; mistuned (celeste) stops, percussion stops, stops of delicate intonation, imitative orchestral color, or poor blending qualities, and all big, tubby-sounding flutes and diapasons which do nothing but thicken the ensemble are best left out of the Tutti and full Crescendo.
Leaving out these elements creates a leaner, more transparent full organ without ANY loss of power; it also tends to minimize or eliminate phasing, i.e., the acoustical interference which can be observed between multiple standing sound waves generated by pipes of different families of sound color sounding at the same pitch.
As always, the ear will decide what to include and what not to include; organists need to trust their ear; when it comes to making adjustments in performance their ear is their best friend; the ear will lead the brain.
Obviously then, the complete freedom which a programmable Tutti piston permits in the composition of the full organ necessitates a complete knowledge of registration and familiarity with the timbre of EVERY stop in the organ in EVERY part of its range, and, in the case of enclosed stops, with the swell shades open, closed, and partially open.
There is an inherent danger of abuse in using this control, not to mention the certainty of a complete destruction of a performance of a piece of music if it is accidentally and unintentionally hit.
This could explain why, if the Tutti piston in a large pipe organ is found to be not working, the reason could very well be that a previous Principal Organist, or perhaps the current one, had it disconnected.
Some years ago at a time when the late Dr. Alexander Schreiner was still serving as organist for the Mormon Tabernacle in Salt Lake City, Utah, he had the programmable Tutti piston disconnected on the big Aeolian-Skinner organ there; this indicates that he not only found no use for it himself but had serious objections to it being provided at all.
Takeaway: how we draw the stops, and how frequently we add or retire them, is balance.
Everything is organ playing is balance.