Commercial Cold-Brew Tea Bags (Size Specs)

For a roughly 1-gallon (3.8 L) batch, start with a cold-brew bag measuring 6 × 9 inches (152 × 229 mm) inside its seams. Use 40 g of dry tea, a nominal 100–200 μm filter opening, and a supplier-documented material suited to aqueous beverage contact. Steep at 4°C (40°F) or colder for 8–12 hours, then validate the result with your tea and vessel.

A loose bag that fits the batch can make tea evenly and simplify removal. A bag that is too small, packed too tightly, or made from an undocumented material can make extraction uneven or leave you unsure whether it is suitable for beverage contact.

I’ve seen the same batch recipe behave differently when the bag’s usable space changes. The improvement comes from treating bag size, tea weight, and water volume as one system, then checking how the tea expands and circulates in the actual vessel.

Bag Material, Dimensions & Batch Prep

A commercial cold-brew tea bag is a filter pouch for holding dry leaves in chilled water. There is no universal commercial size standard, so use the dimensions and dose below as a starting point, not a promise of fit or strength. Confirm the pouch, filter, and food-contact paperwork before using them.

What dimensions and tea charge should I specify?

Usable dimensions are the clear space inside the sealed edges, not the pouch’s outside measurement. A 6 × 9 in (152 × 229 mm) usable bag is a practical starting format for about 3.8 L (1 gallon) of water when charged with 40 g of tea. Check that the bag fits the vessel and can sit below the water.

The starting tea-to-water ratio is about 1:95 by mass: 40 g tea to 3,800 g water. This is a recipe baseline, not a universal strength standard. Tea type, leaf size, and your desired flavor can change the result, so record adjustments and taste-test a batch before setting a production recipe.

These scaled amounts preserve the same starting ratio. They do not prove that one bag can hold the larger charge. Use an appropriately sized bag or more than one bag, and leave room for water to move around the leaves.

How do I choose the filter and material?

Aperture means the approximate size of openings in the filter. For loose-leaf tea, specify a nominal aperture of 100–200 μm, then test whether the selected grade holds enough fines for your beverage while still allowing water to flow. A micron rating alone cannot confirm performance: the tea’s particle size and the filter’s construction matter.

Ask the supplier to identify the exact substrate, such as the specific paper or polymer, and provide documentation for its intended food-contact use. Verify the applicable FDA food-contact basis for that material and use. “Food grade” by itself is not enough to establish what the material is made from or whether it suits your conditions.

Specify sealed seams and a secure closure. Ask for confirmation that the bag is intended for aqueous beverage contact for the planned time and temperature. Cold-brew suitability does not establish that the bag is safe for hot fill, boiling water, or oven use. Do not use a bag if its suitability is unclear.

Key takeaway: Put the usable dimensions, substrate, filter grade, seam design, and closure in the purchase specification. Test the maximum leaf charge in the actual bag before ordering for routine production.

Cold-Steeping Technique & Extraction Control

Cold extraction is steeping tea in chilled water for a set period. For a controlled starting process, use potable, chilled water and hold the covered vessel at 4°C (40°F) or colder for 8–12 hours. The exact time and dose need validation for the tea and strength you intend to serve.

How should I load and steep the bag?

1. Clean and sanitize the vessel and utensils under your site’s HACCP procedures. HACCP means the site’s plan for managing food-safety hazards. Follow the plan and the product directions for the cleaning and sanitizing steps.
2. Weigh the dry tea to match the batch recipe. Add it loosely; the dry tea should occupy no more than half the bag. This leaves room for leaves to expand and for water to circulate.
3. Close the bag securely, then place it in the vessel. Add chilled, potable water and make sure the bag is fully immersed. Cover the vessel.
4. Hold it at or below 4°C (40°F) for the recipe’s validated time, starting with 8–12 hours. Do not assume that longer steeping will improve the tea; check the finished flavor.
5. Keep the bag from being packed tightly against other bags or wedged into a narrow space. Water needs access to the leaves throughout the pouch.

Overfilling or compressing a bag can restrict water movement. That may lead to uneven extraction and tea that tastes weak or inconsistent. During the first test, check whether the leaves can expand and whether water moves through the bag. If not, reduce the charge or select a larger pouch.

How do I validate time and strength?

Make a small test batch using the planned bag, tea, water, and vessel. Record the tea weight, water volume, steep time, temperature, and result. Taste the tea at the end of the chosen steep time, then adjust one variable at a time. That makes it easier to identify what changed the flavor.

These are diagnostic prompts, not guarantees of cause. A particular tea or filter can behave differently, so confirm each change in a controlled batch.

Key takeaway: Keep the cold hold at 4°C (40°F) or colder, and validate the time and dose for the tea you use. Don’t solve a weak brew by packing more leaves into a crowded bag.

Sanitation, Bag Handling & Equipment Care

Sanitation and careful handling reduce avoidable contamination risks and help keep batches consistent. Use the site’s established food-safety procedures, inspect the bag before filling, and handle the finished tea with clean utensils. A bag’s filter function does not replace cleaning, sanitizing, or temperature control.

What should I inspect before brewing?

Check the bag for holes, loose seams, or a closure that will not stay secure. A damaged pouch can release leaves into the beverage. If the supplier specifies handling limits or use conditions, follow them; do not infer suitability from appearance alone.

Use only bags with supplier documentation that covers the actual substrate and intended beverage contact. Do not substitute an unverified pouch, even if it looks similar to the specified bag. If the product information does not establish suitability for the planned cold-water contact, pause and ask the supplier for clarification.

After steeping, lift the pouch and let it drain without forceful squeezing. Pressure can push more tea fines through the filter and may change the drink’s astringency. If your beverage specification calls for clearer tea, decide whether a separate straining step is needed and test it with the finished recipe.

Discard single-use bags and their used tea after brewing. Do not wash or reuse a single-use pouch. Wash, rinse, and sanitize reusable equipment according to your site’s procedures before the next batch.

Implementation cases: checking fit before routine service

These examples are practical test scenarios, not reports of measured results. They show how to use the specification in different vessels without assuming that one bag size will work in every setup.

• One-gallon beverage vessel: Measure the opening and interior depth, then check whether a 6 × 9 in usable bag can be fully immersed without folding tightly. Start with 40 g of tea and 3.8 L of water. Confirm leaf expansion, circulation, and finished flavor.
• Narrow or deep vessel: Test the bag’s path through the opening and whether it can be retrieved without tearing or compressing it. If it cannot sit freely, use a better-fitting vessel or an appropriately sized pouch.
• Larger batch vessel: Scale the tea and water together to preserve the starting ratio, but do not assume a single pouch can hold the scaled charge. Divide the tea among bags and check that they are not crowded together.

Key takeaway: Treat fit as a vessel-specific check. A correct measurement on a supplier sheet does not guarantee that the loaded bag will move freely in your container.

Straining, Chilling & Service Presentation

After extraction, remove the bag carefully and keep the finished tea under the site’s validated refrigerated time-and-temperature controls. Straining is optional unless the beverage needs it. Whether you strain, decant, or serve directly should depend on the drink’s clarity and the equipment used.

What should I do after steeping?

Lift the bag and allow it to drain naturally. Avoid twisting, pressing, or squeezing it. If the finished tea has more visible fines than your service standard allows, test an additional filter step and note whether it changes flow, clarity, or flavor.

Keep the beverage refrigerated under your site’s validated controls. The specified steeping condition of 4°C (40°F) or colder is a process target; it does not by itself set a safe storage period. Follow the site’s food-safety plan for holding time and temperature rather than guessing a shelf life.

Before service, use clean equipment and avoid returning a used tea bag to the beverage. Dispose of single-use bags and tea, then clean, rinse, and sanitize reusable vessels and utensils under the site procedure.

What should the purchase specification include?

Use a written specification so staff and suppliers are working from the same details:

• Usable bag dimensions: 6 × 9 in (152 × 229 mm), measured inside the seams, as the starting format.
• Tea charge and batch ratio: 40 g per 3.8 L water, adjusted only after recipe testing.
• Filter: nominal 100–200 μm aperture, validated for both flow and fines retention.
• Material: supplier-identified substrate with applicable food-contact documentation for aqueous beverage contact and intended conditions.
• Construction: sealed seams and a secure closure.
• Use limits: cold-water brewing only unless separate documentation supports other conditions.
• Process: 4°C (40°F) or colder for a validated 8–12-hour starting window.

Conclusion: The most useful bag specification combines internal dimensions, a controlled tea charge, a tested filter grade, and material documentation. Start with the 6 × 9 in format and 40 g per 3.8 L, then confirm fit, flow, and flavor in your own vessel before standardizing the process.

Frequently Asked Questions

These answers cover common purchasing and brewing decisions for commercial cold-brew tea bags. Use them as starting points, then check the supplier’s documentation and your site’s validated recipe. Bag fit, filter performance, tea strength, and food-contact suitability all depend on the specific product and process.

What size bag should I use for a 1-gallon batch?
Start with a 6 × 9 in (152 × 229 mm) usable bag, measured inside its seams. Confirm it fits your vessel and leaves room for the leaves to expand.

How much tea goes in a 1-gallon cold brew?
A starting charge is 40 g of dry tea per 3.8 L (about 1 gallon) of water, or roughly a 1:95 mass ratio. Adjust only after testing the tea and desired strength.

How full should a tea bag be?
Keep the bag no more than half full when dry. This leaves room for leaf expansion and water circulation.

What filter opening should I specify?
A nominal 100–200 μm aperture is a starting range for loose-leaf tea. Test the selected grade for flow and fines retention with your tea.

How long should I cold-steep tea?
Start with 8–12 hours at 4°C (40°F) or colder. Validate the time for the tea type and strength you want.

Can I use a bag labeled “food grade”?
That phrase alone does not identify the material or establish suitability for your use. Request supplier documentation for the actual substrate and its applicable food-contact basis.

Can I use the bag for hot tea or boiling water?
Do not assume so. Cold-brew suitability does not establish hot-fill or boiling suitability; use those conditions only if the supplier’s documentation supports them.

Should I squeeze the bag after steeping?
No. Let it drain without forceful squeezing, which can push more fines through the filter and may affect astringency.

Can I reuse a single-use cold-brew bag?
No. Discard single-use bags and their used tea after brewing. Do not substitute an undocumented bag.

Why is tea weak even though I followed the recipe?
Check whether the leaves were crowded, the bag was fully immersed, and water could circulate. Then test dose or steep time one change at a time.

(This article was written by one of our staff writers, Daniel M. Whitaker. Visit our Meet the Team page.)