Find the Last Tea Ingredient on Pandora's box.
8 Cinder Horse: In chapter 6, solve Puzzle 109 at the west Y-Junction.
Please see the Related link below for a walkthrough of the last Tea Ingredient.
The last tea ingredient is given with puzzle 109 Walking the Dog
There is NO Bitter Coffee - Only Tea!! on Professor Layton.
Professor Layton and the Diabolical Box. Please see the related link below for a walkthrough of the Character Profiles.
You will need to answer puzzle No 89, Flower Bed Fun, you will then receive Peppercherry Tea Ingredient.
Professor Layton and Pandora's Box. Please see the related walkthrough link
Answer Puzzle 90, The Unusual Fountain to receive the 8th tea ingredient. Please see the Related link below for a walkthrough of puzzle
Receive Tonic Flower tea ingredient by answering puzzle 86. Puzzle 86, Perplexing figures, Location: House in the Alley
Professor Layton and Pandora's Box. Please see the Related link below for a walkthrough of Puzzles.
Puzzle 89, Flower Bed Fun, Location: Clocktower Plaza. Answer = The Red area is 400 square feet. Answer the Above puzzle and receive Peppercherry Spicy Tea Ingredient.
Puzzle 109, Walking The dog, Location: West Y-Junction. Answer the Above puzzle and receive the Cinder Horse Tea Ingredient.
Ray, Go through the broken Gate Leading to the Mine.
Puzzle 94, Location: Museum G-Floor
I just Google 'Professor Layton Cheats', or "Guides", or 'Hints', or 'Walkthroughs'. You also should put in the name of the game (Curious Village, Diabolical Bow, etc.)