Guru 20 - materials are same, cant use 4 grains

Shorting the recipe by even one grain results in a not-insignificant fail rate even at Pro 10, so not really worth the trouble considering how easy it is to get grains.

Cereales: 5 Trigo, patata, Maíz, Camote, Cebada
Agente de Fermentación 2
Azúcar 1
Agua Para Cocinar 6

Strossy - Cooking Artisan 2
1 Special Wheat
3 Purified Water
1 Sugar
2 Leavening Agents
=1-3 Beer / 1-2 Draft Beer + Exchange items.

Artisan 1
using 4 wheat and it's working but not everytime ( it fail at an average of 1 time every 10 try so still worth it if not afk )

Potato 5 / You get it at Loggia farm.
Leavening Agent 2 / You get it at David Finto
Sugar 1 / You get it at David Finto
Mineral Water 6 / You get it at David Finto

Skilled 9, Cooking Utensil.
5 Corn, 3 Purified Water, 1 sugar, 2 Leveraging Agent
queued 39, failed at 3 left, because I ran out of leaving agent :P but so far 100% success rate.

Update:
Just tried it 264 continuous production with 100% success so far.
Though I ran out of corn so started using wheat.

Can anyone give me a guide on substituting water-based things? Do they also have colours?
Help, I havent learned much about water in-game apart from river and distilled...

Tried using 5 mineral water instead of 6 at Skilled 5 and it was failing.

You can substitute 6 Distilled Water, As in "The Workers' Only Drink" Quest in Altanova.

Swet potatoes in Shuri Farm are the best grain to farm, because you get Special and High quality from the same worker/node, therefore exploiting only one node should cover your needs in beer for your worker empire. I have over 100 workers and it works fine with only this node with plenty of extra.

Recipe adjustements for the different grades:

Sweet potato (white): x5;
High-quality sweet potato (green): x2;
Special sweet potato (blue): x1.

1x Special (Wheat/Corn etc)
6x Any Water (Destilled, Mineral etc)
2x L.Agent
1x Sugar

Also works very nicely.
(tested with Cooking Skilled 5)