Grenouille spends his winter in the workshop, supposedly attempting to invent a formula for a new cologne. In actuality, he spends his time creating a number of personal odors for himself. He makes one that allows him to be inconspicuous, one that makes people think he's in a hurry, and one that imitates Druot's odor of semen.
The reader knows that Grenouille is more than capable of creating a wonderful cologne, which draws the reader towards Grenouille's way of thinking that others are stupid and easily fooled.
With the disguise of these perfumes, Grenouille is able to exist undisturbed. He devotes himself to the pursuit of subtle scents and systematically plans how to perfect his methods. He begins extracting scent from a brass doorknob by wrapping it in beef tallow. He moves on to capturing the scent of stone, and creates a perfume of the olive grove behind the cloister in town. These scents delight Grenouille.
It's implied here that Grenouille's joy in these subtle scents and the combinations thereof is pure and innocent, although the reader is aware of what the sinister final goal is. Overall, this passage again works to draw in the reader to empathize with Grenouille.
Next, Grenouille moves on to living subjects. He hunts for small animals and drowns them in warm oil, and creeps into animals' stalls at night to drape oily cloths over them. Animals, unlike inanimate objects, he finds reluctant. Farm animals rub off the cloths, and out of fear, rats defecate and sweat as he attempts to submerge them in the warm oil, ruining it. Grenouille realizes he must kill them first.
Suddenly, Grenouille's innocent experiments turn more sinister and horrifying as he tries to drown live rats in oil. These experiments lead the reader to wonder what method Grenouille will settle on for human subjects.
Grenouille targets a puppy, luring it away from its mother and dealing it a fatal blow as it eats a scrap of meat. He sandwiches the body between two greased plates and lets it sit until it begins to stink. He then distills the oil down into a tiny tube that smells clearly of dog, and when he offers the tube to the puppy's mother, she whimpers and won't leave the scent.
Targeting a puppy mirrors Grenouille's targeting of young girls throughout the novel. This scene shows Grenouille’s capacity for cruelty, as he’s willing to do seemingly anything to pursue his goals.
Cautiously, Grenouille moves on to humans, concerned primarily with testing his methods. He sticks tiny scraps of oily cloth under benches in an inn, but these yield a scent more of the inn than of humans themselves. Over Christmas, Grenouille leaves similar scraps under pews at the cathedral, and the resulting odor is resoundingly human. Finally, Grenouille obtains bed sheets from a man who died of consumption, and is able to extract the man's personal odor from the sweaty sheets. He discovers the perfect type of oil to use by paying a beggar woman to wear oily rags against her skin. He stops at that, as his real goal is to extract the scent of humans who inspire love.
The process here is fascinating as well as somewhat gross, and undeniably sinister. We see Grenouille's scientific mind at work in his method of experiments that grow in complexity and focus in on specific targets. Grenouille's focus on victims that "inspire love" asks the reader to question Grenouille's motives. Does he want them purely for himself so that he might be loved as well, or just because he enjoys these scents most and wants to possess them for himself? Alternately, does he want to deprive others of their inspiration for love?