What mesh size should I use for a hop spider?

For pellet hops, use 300-400 micron mesh. This is fine enough to contain most pellet debris while allowing good wort flow. For whole leaf hops, 200+ micron works well. Avoid mesh finer than 200 microns as it clogs easily during the boil.

Do hop spiders reduce hop utilisation?

Hop spiders can slightly reduce utilisation (5-15%) compared to free-floating hops because the wort circulation through the bag is restricted. To compensate, many brewers add 10-15% more hops when using a hop spider, or gently stir the bag during the boil.

How full should a hop spider bag be?

Aim for no more than 50-60% full when dry. Pellet hops expand 2-3 times their dry volume when they absorb wort and break apart. Leaving headroom ensures the wort can flow through the hops for proper extraction.

Can I use a hop spider for dry hopping?

Yes, a hop spider or mesh bag works well for dry hopping as it makes removal easy and reduces hop debris in the finished beer. For dry hops, a slightly coarser mesh (400-600 micron) is fine since you are not dealing with a vigorous boil.

BrewCalcs

Hop Spider Calculator — Mesh Bag Sizing

Calculate the hop spider mesh bag size needed for your hop additions based on weight and format.

Total Hop Weight

Total weight of all hop additions for the boil

Hop FormatPellets expand more than leaf hops when wet

Kettle Diameter

Internal diameter of your brew kettle

Number of Additions

How many hop additions during the boil

How We Calculate This

Bag Volume Calculation

Required volume = (Hop weight × volume per gram × expansion factor) ÷ fill factor

Pellet hops occupy roughly 3.5ml per gram dry and expand 2-3× when wet. Whole leaf hops are bulkier (10ml/g) but expand less. The fill factor ensures the bag is not packed too tightly for proper wort circulation.

Bag Dimensions

The bag diameter should be roughly 40% of the kettle diameter to allow it to sit inside the hop spider frame. The length is calculated from the required volume and chosen diameter, capped at 80% of the kettle depth.

Frequently Asked Questions

Related Calculators

IBU Calculator

Calculate International Bitterness Units using Tinseth or Rager formulas.

Hop Utilisation Calculator

Calculate IBU contribution, utilisation percentage and bittering versus flavour ratio from alpha acid, hop weight, boil time and wort gravity.

Hop Substitution Calculator

Find equivalent hop amounts when substituting varieties.

Dry Hop Calculator

Calculate dry hop amounts based on desired intensity and batch size.

First Wort Hop Calculator

Calculate IBU contribution from first wort hopping additions.

Last updated: March 2026

All calculations are estimates. Always verify values and adjust based on your equipment and ingredients.