craft beer machine

5.5 Gallon Hop Back

A 5.5 gallon hop back is a piece of brewing equipment used by homebrewers and craft breweries to add hop aroma and flavor to beer. The hop back fits inline between the brew kettle and fermenter to filter and infuse the hot wort with hop oils and resins as it passes through a bed of whole leaf or pellet hops.

Hop Back Equipment Guide

A hop back unit consists of a stainless steel chamber filled with hops through which the hot wort flows. It is usually cylindrical or square in shape with inlets and outlets to connect it to transfer hoses or piping. A filter screen helps separate the hop debris. Hop backs often have sight glasses, thermometers, and valves to control and monitor the transfer.

Types of 5.5 Gallon Hop Backs

CylindricalMost common design, easier to fill and clean than square
SquareCompact footprint, maximizes hop contact area
Single-useDisposable nylon or fabric, reduce cleaning
RotatingMotorized rotation to improve saturation
PressurizedApply backpressure to infuse more oils

5.5 Gallon Hop Back Brewing Process

A hop back is used after the wort has been boiled and cooled down slightly. The process consists of:

  1. Heating wort to a temperature between 165-185°F to maximize hop oil extraction
  2. Transferring hot wort into the inlet of the sealed hop back chamber filled with hops
  3. Allowing the wort dwell time to steep and saturate the hops, typically 10-20 minutes
  4. Draining the infused wort out of the outlet into the fermenter
  5. Cleaning and sanitizing the hop back thoroughly between uses

Specifications of 5.5 Gallon Hop Back

Capacity5.5 gallons
ConstructionStainless Steel, some plastic units for single-use
ShapeCylindrical or Square
Dimensions8-12 inches diameter, 16-24 inches tall
Fittings1.5″ tri-clamp or threaded fittings
Rack mountsAvailable on some models
Thermometer&Sight GlassAnalog or digital thermometer, glass window to observe wort
ScreensStainless steel mesh to filter hops
ValvesBall valves to control flow rates
StandIncluded with some units
InsulationOptional foam wrap or jacket
CustomizationLogo etching, custom fittings or valves

Suppliers and Price Range of 5.5 Gallon Hop Backs

ManufacturerPrice Range
Ss Brewtech$130-$250
Spike Brewing$180-$220
Keg King$120-$180
The Electric Brewery$130-$180

Installation, Operation and Maintenance

InstallationAttach to brewing system via tri-clamps or threaded fittings<br>Position at working height using racking ears or stand
FillingAdd up to 2 lbs whole leaf or 4 lbs pellet hops <br>Spread evenly across screen surface area
OperationControl flow rates using valves to allow 10-20 min contact time <br> Monitor thermometer and adjust heating if needed
MaintenanceRinse immediately after use<br>Brush screen to remove hop debris <br>Clean with PBW and sanitize with StarSan or Iodophor

Choosing a 5.5 Gallon Hop Back Supplier

When selecting a hop back unit, consider the following:

BudgetLower-cost single use models vs professional stainless steel <br> Balance size and features against price
ConstructionStainless steel preferred for durability and cleaning <br> Plastic if only using once
Hop capacityAround 0.5-1 lb hops per gallon capacity
DimensionsMeasure space in brewing system layout
FittingsMatch current equipment fittings
Ease of usePrefer tri-clamp for simple connections and breakdown
Added featuresInsulation, thermometer, sight glass provide convenience
Brand reputationRead homebrewer reviews and feedback

Comparison Between 5.5 Gallon Hop Back Options

Hop contact areaModerateMaximumModerateMaximumMaximum
Wort exposureModerateMaximumModerateMaximumMaximum
Ease of fillingMaximumModerateModerateModerateModerate
Ease of cleaningModerateDifficultEasyDifficultDifficult
Flavor saturationModerateMaximumMinimumMaximumMaximum
Hop debrisModerateMinimumMaximumMinimumMinimum

Summary: Square maximizes exposure but harder to clean. Rotating and pressurized also increase contact but involve added complexity. Single-use models reduce cleaning at the cost of hop utilization.

Pros and Cons of 5.5 Gallon Hop Backs

Boost hop aroma and flavorAdded cost and system complexity
Naturally filter hop debrisTime-consuming to clean and maintain
Allow dry hopping at high krausenCan introduce oxygen if not properly sealed
Compact size for small batchesLimited contact time reduces utilization
Easy to install in brew lineHop particulate can clog ball valves


Q: What size hop back is best for a 5 gallon home brewery?

A: A 5.5 gallon hop back is ideal for 5 gallon batches. It allows room for the full volume plus plenty of hops with minimal headspace. Larger units are better for bigger batches or highly hopped styles.

Q: Can I use a hop back without any additional equipment?

A: Yes, just connect hoses directly from the kettle outlet to the hop back inlet, then more hose from its outlet to the fermenter. Use valves to control flow rates.

Q: How many hops do I need to fill a 5.5 gallon hop back?

A: As a general rule of thumb, use 0.5-1 lbs of whole leaf hops or 1-2 lbs of pellet hops per gallon of hop back capacity. So 2.75 – 5.5 lbs should sufficiently fill a 5.5 gallon unit.

Q: Should I adjust my boil hop additions if using a hop back?

A: Yes, you can reduce late boil hop additions since the hop back will provide equivalent aroma and flavor. But bittering hops should remain the same.

Q: Can I dry hop in the hop back instead of the fermenter?

A: Absolutely, the hop back allows dry hopping at peak fermentation when yeast activity maximizes absorption of hop oils into the beer.

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