What is the game logic for requiring Ritual (and thus a pawn of vis per 5 Mags) to create 'nutritious' food?
Is it to force Magi to have something to do with feudal Europe (otherwise they could settle on deserted islands, icy mountains or deep deserts and still live just fine) or is there some other logic I'm missing here?
Thx.
SJE
My understanding is that it's because Vis is required to create anything permanent. Food that's not permanent will disappear once the duration expires (diameter, sun, what have you). If it's been eaten during that duration, the food disappears, as well as all the nutrients that were in there. Thus, it's for all practical purposes as though you had never eaten the magically-created food to begin with.
Yep, from ametagame point of view pretty much it is that. To prevent magi living totally appart from the medieval society.
Xavi
Magi can settle on deserted islands, icy mountains or deep desert and still live just fine, without need of Vis.
As Peregrine_Bjornaer pointed out, the reason is more one of "self-consistency" of the laws of Hermetic Magic than a metagame one.
Not really, if you create an apple the looks, feels and tastes like an apple and it lasts long enough for you to eat it, digest it and excrete it, then to the mediavael mind it is an apple - they have no concept of calories or or vitamens. The desire for Vis to be needed for permanent durations doesnt really apply as food itself isnt permanent - it spoils and goes rotten eventually.
I agree it seems more of a metagame requirement than one with an in-setting logic.
SJE
So if you eat food created via magic without using vis you'll become hungry like you never ate it and potentially starve to death once the duration expires.
I've never been sure that there is actual confirmation in the RAW on the nutritious food situation. I could be wrong (Maybe it's in Covenants?) but it seems to me just to be the most commonly believed interpretation.
It's actually explicitly stated for vegetable food (check out the "Creo Herbam" guidelines in the corebook).
However, if you create a magical sheep and sustain the spell for long enough (say, within a Ring so you do not need a Ritual), feeding the sheep on mundane food, when the magic expires you have a perfectly mundane, nutritious, sheep corpse (check out the descriprion of Creo on p.77).
Also, if you start out with mundane seeds, you can grow them to full maturity overnight without need of a ritual (check the Creo Herbam guidelines), and the resulting plants are perfectly mundane (and can be used to plant more seeds etc.)
In a nutshell, it takes very little for a covenant to get organized and produce all food it needs.
Yup there it is searched through several books including the main book to find that passage and just missed it. Actually I missed the whole creo write up it's been a while since I read it. I'm curious if you could feed a perfectly natural animal magical food long enough that it would just disappear when the spell expired.
How's this for a Hermetic experiment. Create a large amount of grain with a circle duration. Also trap a colony of mice inside with the grain with an animal ward circle. Eventually you'll have mice in there that have never eaten real food in their lives and neither have their parents onto several generations. Pull mice out one by one as the experiment progresses and see whats left.
Also what a way to contain a dangerous creatures safely.
Yep. But you can do fun things when you start to consider the effects of warping on successive generations of plants.
This is where the arguments start:
Non-Ritual food sustains you , for as long as you eat it , after duration ends , you just feel ravenously hungry.
Non-Ritual food prevents you from suffering the effects of Deprivation ,
but after you fail enough checks , you simply fall unconscious and eventually die of starvation.
If the magically-created horse becomes wholly mundane after a year of mundane food , is the reverse true?
That a mundane body becomes sustained and replaced by spell energy , if no mundane food is given to them.
This becomes a form of torture for your enemies.
Once they are sufficiently dependent on your magical food , threaten them with withholding it.
I would probably say the ground gets robbed of its nutrients quickly if you do this a lot. The idea of fields lying fallow was certainly around.
I must be remembering something incorrectly. I thought you could not get viable seeds from those. Maybe that was from CrHe-created plants? I'll have to search and see which things I'm mixing up.
Chris
Rego Herbam for fast growth is where you dont get seeds.
(this can be quite useful at times though)
You could use momentary Creo rituals to "heal" the fields , if you overuse the growth option , but can be costly in terms of vis.
Rego Craft magics to replace soil quickly with that from another area and to spread fertiliser (manure).
You're right, you can't get viable seeds this way. This is one of several places where the rules intentionally introduce complications to make it hard to live by magic alone. The bigger complication is of course the one making visless magical food lack nutrition, even though absolutely everything else created (fire, water, shelter, etc.) has effects that remain after the creation itself expires. It's totally a game device to keep Covenants tied to the mundane world.
The hard part for me is making this connection square with the Order's apparent insistance on not involving itself in mortal affairs. Someone tell me how huge covenants like Durenmar, in the deepest darkest part of the Black Forest, feed themselves and how they at the same time manage to keep themselves out of regular dealing with kings and nobles that would violate the Code.
Durenmar is a mercere portal hub, so nort much problem here. I can see the problem with less well-connected covenants, though. Nice catch.
Xavi
Check out the Creo and (particularly) Rego descriptions from the Hermetic Magic chapter.
That third is probably the best way to use non-ritual magic for creating food, particularly combined with Circle/Ring spells or even permanently enchanted pots, although Rego is good for fresh fruit 
There could be issues of pollination. They don't have a lot of time for the bees to get at them.
Create 1 seed: CrHe2
Boost to group (10 seeds) CrHe4. Boost to 100 seeds, CrHe5, Boost to 1,000 CrHe10. Boost to 10,0000 Crhe 15. Boost to 10,0000 CrHe20.
I guess that would be enough to create enough seeds to plan some stuff around. ReHe to make them grow and you can sustian yourself rather easily with magic alone for not so big a vis cost. If that is what you want, that is.
Cheers,
Xavi
Ah, that's it. Thanks. I was remembering the ReHe version. I now see how you're doing things differently.
I'm not sure about the CrHe version, though. For example, I wouldn't expect making a little girl become a mature girl would also make her pregnant. I would expect an apple tree, for instance, to become full-grown but have no apples upon it. I suppose that's why you're considering only certain types of plants, such as wheat, so that you're looking at the plant as a whole and not just the fruit or similar it bears. I see the approach you're taking and how it might work, but I'm not sure I buy it yet.
Chris
It slipped my mind that there were two ways to mature plants, with seemingly different results. If I had to guess, I'd say the intent of the game is to make growing food difficult and that the CrHr option isn't meant to be free of complications.
There's something very amusing about the thought of cattle being driven through a Hermes Portal. 
You're right that Durenmar ought to be able to solve the problem somehow. In general I find it confusing that magi and covenants are pushed towards mortal society and at the same time prohibited from taking a meaningful part in it, due to the Code as well as because of basic logistics like the forest. I think we're looking at different strata of rules/background built up over five editions in a way that's no longer consistent.
You are not required to buy anything , David Chart won't be sending Hoplites your way after all.
Mature women are not naturally pregnant with unborn children.
If you want the detail that any plant that requires pollination will not bear fruit , do so.
However , any plant that naturally grows seed as it matures , be it grass-like plants such as wheat
or plants that have fruit containing seeds , will have them if matured by Creo magic.