Alchemical Adept

You are an adept potion and poison maker! 

Once per day, name the potion or poison you are attempting to create to your DM along with the amount of time you intend to spend gathering ingredients and the amount of time you intend to spend crafting said product (capped at 8 hours per task). Make a Nature or Survival Check to gather ingredients, followed by an Alchemist's supplies, Herbalism kit, or Poisoner's kit check to craft your potion or poison. The DC of both checks is set according to the rarity of the intended product (see table bellow) minus the amount of time spent on each tast (-1 per hour, capped at 8 hours per task, eg 5 hours spent gathering and 6 hours spent crafting gives you a -5 to your Nature/Survival check DC and a -6 to your Alchemist's supplies/Herbalism kit/Poisoner's kit check DC). 

Should you pass your crafting check by 10 or more and the intended product has a more potent but rarer variant, you now craft that product one step up the rarity chain (eg a common Healing Potion becomes an uncommon Potion of Greater Healing). Should multiple improved versions of your intended product exist with equal rarities, create the potion one direct step up from your intended product (eg uncommon Potion of Hill Giant Strength upgrades to a rare Potion of Frost/Stone Giant Strength despite the Potion of Fire Giant Strength also being listed as rare, since the Frost/Stone Giant version is one direct step up).

Pass your gathering check by 5 or more and double the amount produced on your following crafting check. Additionally, should you fail the following crafting check you may attempt it a second time, now producing a single product on a success instead of double.
Pass your gathering check by 10 or more and triple the amount produced on your following crafting check. If you fail said crafting check, you may make up to two additional attempts (producing double on the second roll and a single product on the third).
Pass your gathering check by 15 or more and quadruple the amount of product created on your following crafting check, or gain 3 additional attempts to craft (producing triple, then double, then a single product).

For poisons follow the rarity table bellow to determine the equivalent gathering and crafting DC. The rarity of any poison created from a poisonous creature is "common" however said poison can only be harvested from said creature's dead or incapacitated body. Harvesting a poisonous creature that doesn't have a specified correlating poison produces a Vial of Basic Poison. Poisonous creatures can only be harvested once and poisonous creatures that have been dead for too long may no longer be harvestable, as determined by your DM. All poisons have a +5 to any DC made to craft.

Legendary items can only be created with at least three separate successful attempts (6 total rolls: 3 gathering, 3 crafting, over at least 3 days) . Should any check fail while in the process of creating a Legendary item the entire brew is ruined and you must begin again from scratch, additionally roll a D20, on a 1 the concoction explodes, all creatures in a 15ft radius must succeed a DC 13 Dex save or suffer a random magical effect decided by your DM.

If you are in a lifeless area all checks to gather automatically fail, if you are in a desert, tundra, or any other harsh environment mostly devoid of life the DC to gather is now +10. If you fail your gathering check you can not attempt a crafting check.

Potion Rarity/DC Chart:
Common - DC 10
Uncommon - DC 15
Rare - DC 20
Very Rare - DC 25
Legendary - DC 30

Poison Rarity Chart:
Assassin's Blood - Uncommon
Burnt Other Fumes - Rare
Crawler Mucus - Common - only available when searching a dead or incapacitated Crawler.
Drow Poison - Uncommon - only available in a place far removed from sunlight, additional +10 crafting penalty unless crafter is a Drow or has received instructions/training from a Drow.
Essense of Ether - Rare
Malice - Rare
Midnight Tears - Very Rare
Oil of Taggit - Uncommon
Pale Tincture - Rare
Purple Worm Poison - Common - only available when searching a dead or incapacitated Purple Worm
Serpent Venom - Common - only available when searching a dead or incapacitated giant poisonous snake.
Torpor - Rare
Truth Serum - Common
Wyvern Poison - Common - only available when searching a dead or incapacitated wyvern Vial of Basic Poison - Common
Basic Poison - Common