I've seen wiki's etc, which claim a certain potion or oil lasts for a specific duration and that the quality of a 'base' determines the number of ingredients you can use. But since you can often acquire far more ingredients than you are likely to use in a Chapter, you can also sell ingredients.
When you sell ingredients that have exactly the same properties, some can sell for 20 times more than another. So if a 'base' has a quality, do ingredients have qualities too? In other words, is a 4 hour oil going to be an 1/2 hour oil or an 8 hour oil depending upon what ingredients I use, or should I just sell the expensive ingredients and keep the cheap ones?

It's been a while but IIRC 'base' refers to the quality of the alcohol you use. The better the quality, the more ingredients you can use. Thus some potions require 'better' alcohol while other will work with the cheap stuff.

That's what I said. But can you answer my questions about ingredients?

No. The expensive ingredients (like Albar's crystals etc.) are supposed to improve Geralt's budget.

What MaxStrauss wrote is true. For role playing , I like to believe that the reason is trying to emulate "real life". Powdered Pearl should be more expensive than Helleborne Petals.

With regards to quality, some ingredients have secondary properties. Having one of these properties could make that ingredient more desirable to you than an ingredient without that property. The secondary properties are:
Albedo - lowers toxicity
Negredo - increases the damage you do
Rubedo - increases health regeneration

If all of the ingredients used in your potion have the same secondary property they provide the benefit of that property in addition to the potions main benefit.

e.g One of my favorites is Tawny Oil with Rubedo, it increases both endurance and health regeneration. The formula is:
Vitrol with Rubedo (Sewant Mushroom, or Calcium Equum, or Bruxa Blood), plus
2 Aethers with Rubedo (Alp Fangs, Helleborne Petals, or Powdered Pearl). The Aether ingredients can be either the same or mixed, as long both have Rebedo.

Thanks MaxStrauss & JoeAboveAverage,
Although I haven't made a bomb yet, I use my 'pure' ingredients for Oils, and my ingredients with secondary properties for Potions. In fact, I've even taken to making making White Gull Potions which have a secondary property and using them for potions which need a 'high' or 'top' quality base..

Another question though... Things like Barghest Skulls and Fleder Fangs claim to be ingredients, but they don't go into my ingredients pouch; instead take up space in my inventory. Will I eventually gain the knowledge that turns these ingredients into ingredients I can use or are they just another source of cash and more of a minor trophy rather than an ingredient?

Also, your thoughts about Witcher 2?
Thanks

Right. Not necessary - or even counterproductive. White Gull is the universal potion base - regardless of the secondary substances. Different versions of White Gull fill your inventory. Later on you need the space. Yes. But Barghest Skulls and Fleder Fangs - as well as other teeth - are important for a secondary quest in Chapter 3 which will provide a very good sword in chapter 5. So spare one of these items, store them in the inn and sell the rest. Don't forget to take them along before you start chapter 5 - there will be no inn!

Thank you MaxStrauss.

The wiki on witcher potions claims that White Gull potions do not make potions with additional effects unless the White Gull potion itself has that additional effect.
I gather that information is incorrect, or was once correct but has changed because of some patch?

As for storage, yes; I have hundreds of each kind of ingredient I know stored and carry minimal stuff.
I'm only in Chapter Two, have bought the better armor, read every book the Antiquarian sells, got my 3 blue meteorite sword, and am currently grinding to get enough levels to enter the swamp.

About that better sword, and others I will get along the way... would I be correct in assuming they are not replacements for my witchers swords but additions I'll only use for specific missions? In other words, are meteorites and runes just another thing I should be selling?

A second question. Although I intend to ally with the non-humans, considering the 'human' blacksmith is closest to the inn, is there a best time to refuse Siegfried's offer to join The Order of the Rose?

Once you get a better sword, there's no reason to keep using the old ones. I don't think I even had to forge new swords, I ended up using the ones you get as rewards for quests. I did buy new armors though and those clearly made a difference mid-game.

Not really. But convince yourself: Brew an Albedo-Tawny Owl with a neutral White Gull-Base. Your meteorite sword will bring you to chapter 4; here you can buy a better sword just at the beginning (3000 Orens) . You can sell your meteorite sword after acquiring it. (This means: Replacement). Concerning your Silver Sword: Buy a rune from Thaler in chapter 2; you get one rune from Zoltan. At the beginning of chapter 3 you'll get a third rune (fist fight); now you can get a rune sword early in the chapter. End of chapter 4 Geralt will own a much better sword for free. No. As soon as you got your new armour and sold the old one to the order blacksmith for 500 Orens it doesn't matter. Ok, perhaps you have to run some steps additionally, but after doing quests in favor of the squirrels you have to change the blacksmith anyway.

Btw.: Fortunately grinding in TW1/2/3 isn't necessary. One Swallow and one Tawny Owl, a skosh of Igni - and you will be fine in the first chapters.