A LiquidStack consists of a Liquid Definition as well as an optional tag and an optional amount value.

It might be required for you to import the package if you encounter any issues (like casting an Array), so better be safe than sorry and add the import.
import crafttweaker.liquid.ILiquidStack;

An ILiquidStack can be created by using the Liquid Bracket Handler

ZenScript
 Copy
//see The liquid bracket Handler for further information
val lava = <liquid:lava>;

//liquid.withTag(Tag as IData)
val lavaWithTag = <liquid:lava>.withTag(DATA);

//liquid * amount in millibuckets (-> 1000 = 1 Bucket)
val lavaWithAmount = <liquid:lava> * 1000;

As an ILiquidStack represents a liquid, there surely must also be a way of retrieving the fluid's properties.
Check the table to see what you can retrieve from the ILiquidStack Object using ZenGetters.

Zengetter	What is this?	Return Type	Example
Zengetter nome	What is this? This returns the unlocalized liquid name	Return Type string	Example test = <liquid:lava>.name;
Zengetter displayName	What is this? This returns the localized liquid name	Return Type string	Example test = <liquid:lava>.displayName;
Zengetter amount	What is this? This returns the amount of the ILiquidObject	Return Type int	Example test = <liquid:lava>.amount;
Zengetter luminosity	What is this? This returns the luminosity of the referred liquid	Return Type int	Example test = <liquid:lava>.luminosity;
Zengetter density	What is this? This returns the density of the referred liquid	Return Type int	Example test = <liquid:lava>.density;
Zengetter temperature	What is this? This returns the temperature of the referred liquid	Return Type int	Example test = <liquid:lava>.temperature;
Zengetter viscosity	What is this? This returns the viscosity of the referred liquid	Return Type int	Example test = <liquid:lava>.viscosity;
Zengetter gaseous	What is this? This returns whether the referred liquid is gaseous	Return Type boolean	Example test = <liquid:lava>.gaseous;
Zengetter tag	What is this? This returns the ILiquidObject's tag	Return Type IData	Example test = <liquid:lava>.tag;
Zengetter definition	What is this? This returns the referred liquid's definition (see below)	Return Type ILiquid Definition	Example test = <liquid:lava>.definition;

Java Jargon: ILiquidStack implements IIngredient. In other words, all methods that can be used in IIngredients can also be used for ILiquidStacks Refer to the IIngredient entry for further information on this. Here are some special cases, as liquids just aren't items

• You can't mark ILiquidStacks, and you get null of you try to retrieve an ILiquidStack's mark
• .items returns an empty List
• .itemArray returns an empty Array
• .liquids returns this liquid as ILiquidStack (so, exactly this object)
• LiquidStacks can't have Transformers and asking for transformers always returns false
• LiquidStacks can't have Conditions (.only doesn't work)
• Matching with items always returns false