In what industry would the phrases "soft ball", "firm ball" and "hard crack" be used?

1. Thread Stage
When sugar reaches the thread stage, it forms web-like strands when dripped 2" above the pot. It will still have a thin and watery consistency.
What Temperature Is Thread Stage?

The thread stage begins at 230 degrees Fahrenheit (106 degrees Celsius).
Thread Stage Candy:

Thread stage sugar can be used for making sugar syrups, fruit liqueurs, and jellies.

2. Soft Ball
The thread stage is followed directly by the soft ball stage. To test your candy temperature, you'll want a bowl of cool water to drip the sugar into. You'll know you've reached the soft ball stage when the sugar forms a small ball in the water. The ball will quickly flatten after a few moments of handling as it warms in your hand.

What Temperature Is Soft Ball Stage?
The soft ball candy stage begins at 235 degrees Fahrenheit (112 degrees Celsius).

Soft Ball Stage Candy:
You can stop at the candy soft ball stage when making fudge, fondant, pralines, buttercreams, and meringues.

3. Firm Ball
The firm ball stage follows the soft ball stage in the candy-making process. At this temperature, sugar creates a solid ball when dripped into chilled water. This ball can be flattened with some pressure when squished between your fingers.

What Temperature Is Firm Ball Stage?
The firm ball stage forms at 245 degrees Fahrenheit (118 degrees Celsius).

Firm Ball Stage Candy:
The firm ball candy stage is perfect for making creamy caramel candies.

4. Hard Ball
In the candy hard ball stage, heated sugar creates rope-like strands when dripped into water. Once in the water, the sugar will form a solid small ball that is pliable and can be squeezed or pulled.

What Temperature Is Hard Ball Stage?
The hard ball candy stage forms at 250 degrees Fahrenheit (121 degrees Celsius).

Hard Ball Stage Candy:
At the hard ball stage, you can prepare marshmallows, toffee, nougat, rock candy, and gummy candy.

Firm Ball vs Hard Ball
The difference between the firm ball and hard ball candy stage is that in the firm ball stage, sugar can be flattened with some pressure between the fingers while it requires a bit more effort in the hard ball stage. The firm ball stage is used for creamy candies while the hard ball stage can be used to make gummy candies.

5. Soft Crack
You'll see the soft crack candy stage begin with the appearance of small bubbles rising to the surface of the sugar. At this stage, the sugar will separate into brittle threads that bend slightly before breaking when handled.

What Temperature Is Soft Crack Stage?
The candy soft crack stage begins at 270 degrees Fahrenheit (132 degrees Celsius).

Soft Crack Stage Candy:
The soft crack stage is perfect for making delicious butterscotch, taffy, and candy apples.

Hard Ball vs Soft Crack
The difference between the hard ball and soft crack candy stage is that sugar is still rather pliable in the hard ball stage while it will bend and break in the soft crack stage. You can make soft candies, like marshmallows and toffee, with the hard ball stage and tougher candies, like taffy and candy apples, in the soft crack stage.

6. Hard Crack
In the hard crack candy stage, sugar will spread into brittle threads in the cool water. When handled, these threads will snap easily.

What Temperature Is Hard Crack Stage?
The candy hard crack stage takes shape around 300 degrees Fahrenheit (149 degrees Celcius).
Hard Crack Stage Candy:

You can make hard candies like lollipops and brittle once you reach the hard crack stage.

Soft Crack vs Hard Crack
The difference between the soft crack and hard crack candy stage is that, while you can bend sugar in the soft crack stage before it breaks, candy in the hard crack stage snaps quite easily when force is applied. The soft crack stage is used for semi-tough candies like taffy and butterscotch, while the hard crack stage can be used to make hard candies, such as lollipops and brittle.