How does one create skill-enhancing potions in Dresden Files RPG?

Question

Introduction

A couple of friends and I recently picked up the Dresden Files RPG and are currently revving up for our first (real) session.

I'm playing a wizard-esque character whose thaumaturgy is specialized in Crafting. To that end I want to prepare a couple of potion recipes to draw from once we start playing.

Aspect-placing potions seem pretty straight-forward and is no issue, but where I'm drawing up short is in the skill-replacing and/or enhancing potions.

What I'm looking for here is answers to a couple of highly related questions as well as a walkthrough-esque answer to an example.

Here goes.

The Example

I would like to create a potion that would grant the imbiber a Great (+4) bonus on their Weapons (or any skill for that matter) rolls for the duration of the scene.

How would I go about creating such a potion, if it's even possible?

The questions

1. Can potions replace any skill and, if so, do they add to or "replace" the roll?
2. What is the standard duration of a potions effect?
3. How does one go about increasing the duration of a potions effect?

Answer 1

Skill based potions are one of the most frequently misunderstood potions of the system. You brew a potion that can replace one skill for a roll -- not for the length of a scene. The strength of the potion is the strength of the skill. If you craft at strength 5, then you gain a potion that will let you treat a skill as if it were five for one roll. You can do this with any skill where the table agrees it makes sense, which means that a good story teller can usually replace most (if not all) skills.

You do not get to 'add' to an existing skill, only replace. This is because potions can otherwise become insanely overpowered. At Submerged (10 refresh, 35 skill points) my wizard can 'easily' craft a strength 8 potion with multiple uses. The limits seem strict, and make these types of potions seem weak at lower power levels, but the consequences of handwaving them... well, they get really potent, really quick.

Of course, this is up to you and your DM -- if you want to handwave these limits away, that's up to you. Every table is different.

Answer 2

Can potions replace any skill and, if so, do they add to or "replace" the roll? Replace, not add. So it's only an enhancing potion if its shifts are greater than the imbiber's skill.

What is the standard duration of a potions effect? One "exchange" (example in YS 281, "the thaumaturgical effect on this potion will provide five shifts of 'Sprinting' in a single exchange").

How does one go about increasing the duration of a potions effect? By default, make more potions, and imbibe more potions.

Two alternatives:

Use enchanted items instead of potions, because the rules for enchanted items already provide what you want from your potions.

Or,

Make up a Stunt which will allow a wizard to make "better potions" and (important!) come up with appropriate costs and restrictions for the Stunt.

Answer 3

All these answers are wrong about duration and lasting effects.

The standard duration of a potion depends on many factors. The example potion on YS281 is an very powerful thaumaturgic effect (pass through any barriers) in exchange for a very short duration. The default duration of a potion is 1 scene and I will expand on why shortly. First, why is the example 1 exchange?

"The thaumaturgical effect on this potion will provide 5 shifts of “sprinting” in a single exchange—including the ability to pass through normally impassible barriers, like walls."

Please take particular note of the part that says "including the ability to pass through normally impassible barriers". Because of this and the desired effect outcome the time is shortened to a "moment" (not an exchange). The distance is 5 shifts of sprint, but the effect is instantaneous as explained on YS265 under Duration and Enhanced Evocation and YS266 under Short-Term Spells. You sacrifice duration to lower complexity, allowing for powerful effects like "the ability to pass through normally impassible barriers". Exchanges are for evocations, the time table on YS315 is for thuamaturgic effects in most cases, including this one.

There is literally nothing that says that potions only work for 1 roll or 1 exchange by default. Again the default duration of effect is 1 scene. You can look at the list of example potions as a guideline also on YS303. Many of them specify 1 scene for duration. There is nothing that says you can only use it for 1 roll during that scene and that would not jive with how thaum works, thaum is not evo. Enchanted items replicate evocation and are reusable for stress in a very similar manner to rotes, potions replicate evocation OR thaumaturgy and are single use only.

If you make a potion that gives you a skill of +4 for 1 scene then you have a +4 on that skill for the whole scene. Saying that someone should use a stunt or enchanted item is not correct.

TL;DR Potions can give thaum effects and durations, and the default duration is 1 scene in most cases.

EXAMPLES

From YS303:

• Bob’s “Love” Potion Duration: One scene

• Red Court Antivenom Duration: One scene

• Scent Suppression Duration: Several hours, or one scene if the potion is shared among two or three people.

• Stimulant Duration: One scene

• True Seeing Ointment Duration: A few hours, shorter if shared among two people.

From http://www.rickneal.ca/?p=654 (probably the best know DFRPG blogger):

• Shadow Juice Duration: One scene

• Bottled Confidence Duration: One scene