A bunch of grapes (also called a grape cluster) consists of several key parts, each with specific roles and characteristics:

• Peduncle : This is the main stem that attaches the entire bunch to the vine shoot. It is cut during harvesting to release the bunch from the vine

• Rachis : The main branch or axis of the bunch, extending from the peduncle. It serves as the central framework from which smaller branches grow

• Shoulders or Branch-twigs : These are lateral branches coming off the rachis. They can be prominent and sometimes form a "wing" if a large lateral branch develops its own cluster of berries

• Pedicels (Cap stems) : Short stems that connect each individual grape berry to the rachis or its branches. Each pedicel holds one grape

• Grape berries : The individual fruits attached to the pedicels. Each berry has several parts:
  • Skin : Contains pigments and tannins that influence the wine's color, aroma, and flavor complexity. The waxy coating on the skin (pruina) hosts natural yeasts important for fermentation

* **Pulp** : The juicy interior, rich in water, sugars (glucose and fructose), acids (tartaric, malic, citric), and vitamins. It provides the must for winemaking

* **Seeds (Nuggets)** : Usually 2-4 seeds inside each berry, which can affect bitterness if grapes are harvested before seed ripeness

• Stems (Scratch) : The twigs and framework that carry nutrients from the vine to the grapes. They start green and photosynthetic but lignify (turn woody) as they mature. Stems contribute 2-5% of the bunch weight and can influence wine flavor, especially in whole cluster fermentation

In summary, the bunch is a complex structure with a main stem (peduncle), a central axis (rachis), lateral branches (shoulders), and pedicels holding individual grapes, each grape having skin, pulp, and seeds. The stems and rachis transport nutrients and can impact wine characteristics depending on how the bunch is processed