Written by Lara Yehia. Lara researches home and kitchen products for Cupindy.
Published November 2026 · Last reviewed 4 Nov 2026 · Cupindy is not affiliated with any brand on this page.
The short answer
Yes. Domino says brown sugar hardens when its moisture evaporates, so keep it in a rustproof container with a tight-fitting lid, somewhere cool and out of the fridge. Glass or plastic both work if the lid truly seals. For flour and white sugar, size matters more than material.
As an Amazon Associate we earn from qualifying purchases.
Our quick picks
For brown sugar
Rubbermaid Brilliance Pantry Container, 7.8 cup
Clear BPA-free Tritan plastic, a latched lid with a seal, and a listing that names brown sugar as its job. It is freezer-safe and top-rack dishwasher-safe, per the listing.
See the Rubbermaid container on AmazonThe drawback: no moisture disc in the box. In a dry kitchen you add a terra cotta disc yourself.
In glass
ComSaf Square Glass Jars, 78 oz, 3-pack
Glass jar, glass lid, silicone gasket and a wire clamp. ComSaf says each jar takes a 4 lb bag of sugar, and its mouth fits a 1-cup measuring scoop.
See the ComSaf glass jars on AmazonThe drawback: the clamp is metal. ComSaf suggests hand-drying it after washing to prevent water spots or rust.
Capacities, materials and washing rules below are from each Amazon US listing, read 4 Nov 2026. Storage advice is from Domino, King Arthur Baking and three university Extension services, cited at the end.
The 4 best airtight pantry containers at a glance
As an Amazon Associate we earn from qualifying purchases.
| Pick | Material, size and one rule | |
|---|---|---|
|
Rubbermaid Brilliance 7.8 cup Brown sugar |
BPA-free Tritan plastic, 7.8 cups (1.8 L). Top rack only in the dishwasher. | See it |
|
Progressive ProKeeper 1.5 qt Brown sugar, with a disc |
Plastic body, silicone seal, terra cotta disc. Sized for a 2 lb bag, per Progressive. | See it |
|
ComSaf 78 oz glass, 3-pack White sugar, oats |
Glass jar and lid, metal clamp, 78 oz (2.3 L). Hand-dry the clamp. | See it |
|
ComSaf 4 qt glass, 2-pack Flour |
Borosilicate glass, bamboo lid, 4 qt (3.8 L). About 4.4 lb of flour each, per ComSaf. | See it |
Glass or BPA-free plastic for dry goods?
Both keep dry food dry when the seal is good. That is the part every source agrees on. Where they differ is soft plastic, thin bags and bare metal. Here is what each one says, in its own words:
- Domino (brown sugar): "a rustproof container with a tight-fitting lid." It also accepts a re-sealable, moisture-proof plastic bag. Glass and plastic both qualify; a metal tin that can rust does not.
- King Arthur Baking (flour): "an airtight container or bag," in a cool, dark place. It also mentions decanting into "a glass canister or other container."
- Utah State University Extension (pantry bugs): "air-tight, rigid plastic or metal containers." That page does not mention glass.
- Kansas State Research and Extension (pantry bugs): insects "can penetrate any packaging except glass and metal," and "Glass jars with screw-on lids are best." It also lists plastic containers such as Tupperware. None of our glass picks has a screw-on lid; the clamp and gasket lids are the closest match.
- University of Illinois Extension (pantry bugs): "tightly closed glass, metal, or heavy plastic containers."
Both seal. Glass is heavier; plastic is lighter and survives a drop.
No source on that list rules out glass, or rigid plastic with a real seal. The rest is weight, breakage and care. Glass is heavier, and ComSaf warns against sudden temperature changes. Clamp jars add a metal part that can rust if left wet. Rubbermaid calls its Tritan plastic shatter-resistant.
If you are weighing plastic for food in general, our guides to plastic grades for food storage and whether plastic food containers are safe cover the research. For leftovers rather than pantry goods, see glass vs plastic food storage containers.
Best airtight container for brown sugar
For brown sugar, get a container with a latched lid and a silicone seal, sized for the bag you buy. Domino says brown sugar hardens when its moisture evaporates, so the seal does most of the work. If it dries out anyway, a dampened terra cotta disc brings it back.
Domino's storage page is short and specific. Brown sugar "should be stored in a cool, moist area in a rustproof container with a tight-fitting lid." It also says: "Don't store brown sugar in the refrigerator." If you live somewhere very dry or plan to keep a bag for a long time, Domino says you may want to freeze it, then thaw it and break the clumps with a fork.
As an Amazon Associate we earn from qualifying purchases.
Brown sugar pick
Rubbermaid Brilliance Pantry Container, 7.8 cup
Good for: a 2 lb bag of light or dark brown sugar, opened and used over a few months.
Why we picked it: its listing names brown sugar as the job, and 7.8 cups leaves room to spare: Progressive sizes its 1.5 qt (6 cup) keeper for a 2 lb bag. The latches lock, the seal is airtight per Rubbermaid, and the box stacks with other Brilliance sizes.
What to know: BPA-free Tritan plastic, freezer-safe and top-rack dishwasher-safe, per the listing. Rubbermaid sells the same line from 1.3 to 19.9 cups.
The drawback: there is no moisture disc in the box, so a very dry kitchen needs one added.
See the Rubbermaid container on Amazon
Brown sugar keeper
Progressive ProKeeper Brown Sugar Keeper, 1.5 qt
Good for: a dry kitchen, or anyone whose brown sugar keeps going hard even in a sealed box.
Why we picked it: it ships with a tamper and a terra cotta disc, which Domino names as a way to put moisture back. Progressive says the 1.5 qt (1.4 L) body "stores a standard 2 lb bag of brown sugar."
What to know: the listing names ABS, PP, SAN, silicone, stainless steel and terra cotta, and says BPA-free and dishwasher-safe.
The drawback: it holds one 2 lb bag and nothing more. If you keep light and dark brown sugar, you need two.
See the ProKeeper on Amazon
A dampened terra cotta disc sits on the sugar and slowly gives back moisture.
Domino lists the disc among its ways to bring moisture back, with damp paper towels, bread and marshmallows. Domino treats the disc as a fix for sugar that has already hardened; the ProKeeper builds one in.
How to soften brown sugar that has gone hard
Domino gives three methods. The first two are for sugar you need now; the sugar comes out hot and hardens again as it cools, so soften only what you will use.
- Oven: preheat to 250°F (121°C), spread the sugar on an oven-safe pan and heat it until it softens, watching it closely. Measure it right away.
- Microwave: put the sugar in a microwave-safe bowl, cover it with two wet but not dripping paper towels, cover the bowl tightly with plastic wrap (cling film) and heat on HIGH for 1 1/2 to 2 minutes. Break it up with a fork.
- Over about 2 days: seal the sugar in a container with a dampened terra cotta disc, one or two slices of bread, one or two large marshmallows, or damp paper towels on plastic wrap or foil. Domino says to take the extra item out after about 2 days, or once the sugar has softened.
Best airtight containers for flour and sugar
For flour and white sugar, any airtight jar or box works; King Arthur's advice is about the seal, a cool spot and darkness, not the material. Size is the real choice. A 5 lb bag of flour is about 19 cups, more than a 4 qt jar holds.
For white sugar, Domino's whole rule is: "Store in an airtight container to keep sugar free flowing." It adds that granulated sugar "will harden when exposed to any type of moisture." For flour, King Arthur suggests sliding the whole bag into a container if it fits, which keeps the best-by date in view, and says to keep flour in the freezer for long-term storage, to extend its shelf life.
As an Amazon Associate we earn from qualifying purchases.
Flour pick
ComSaf Glass Flour Jars, 4 qt, 2-pack
Good for: all-purpose or bread flour, scooped by hand with a measuring cup.
Why we picked it: the opening is about 5.9 inches (15 cm) wide, so a hand and a cup fit inside. ComSaf says each jar holds about 4.4 lb of flour; at the 4 qt in its specs, our math says closer to 4 1/4 lb. The box includes 1-cup and 1/2-cup plastic scoops.
What to know: borosilicate glass, which ComSaf rates from -4°F to 302°F (-20°C to 150°C), with a silicone ring in the bamboo lid. The glass is dishwasher-safe; ComSaf says to hand wash the lid so it does not warp.
The drawback: a full 5 lb bag of flour will not fit in one jar.
See the ComSaf 4 qt jars on AmazonSugar pick
ComSaf Square Glass Jars, 78 oz, 3-pack
Good for: a 4 lb bag of white sugar, oats, pasta shapes or coffee beans.
Why we picked it: glass jar and glass lid with a silicone gasket, closed by a wire clamp. ComSaf says it takes a 4 lb bag of sugar, which matches our math below, and a standard 1-cup scoop.
What to know: the listing says lead-free and dishwasher-safe; ComSaf adds no microwave and no boiling water into a cold jar. Each jar is 10 inches (25 cm) tall, so check your shelf.
The drawback: the clamp is metal, and ComSaf suggests hand-drying it after washing to prevent water spots or rust.
See the ComSaf 78 oz jars on Amazon
A wide mouth lets the measuring cup in. Narrow jars mean pouring flour, which means mess.
Won't finish whole grain or nut flour before its best-by date? King Arthur says to put it in a plastic bag, or an airtight container if you have the room, and freeze it.
Rice, oats and cereal
The same rule applies: a tight lid, sized to the box or bag. One listing claim needs a pinch of salt. ComSaf says its 78 oz jar holds a 5 lb bag of long-grain rice. King Arthur's weight chart puts dry long-grain rice at 99 grams per half cup, which makes 5 lb about 11 1/2 cups. The jar holds 78 fl oz, about 9 3/4 cups. Plan on roughly 4 lb of rice per jar.
For cereal, a tall narrow box pours better than a wide jar. The Rubbermaid Brilliance line comes in sizes up to 19.9 cups, and our pantry organization guide covers shelf layouts. Short on space? See the small pantry guide.
What size holds a 2 lb or 5 lb bag?
Listings give capacity in cups, ounces or quarts, but you buy food by the pound. We converted with King Arthur's ingredient weights: all-purpose flour 120 g a cup, granulated sugar 198 g, packed brown sugar 213 g.
| Bag | Room it needs (our math) | What fits |
|---|---|---|
| 2 lb brown sugar | About 4 1/4 cups packed (1 L). Loose from the bag it takes more. | Rubbermaid 7.8 cup, ProKeeper 1.5 qt |
| 4 lb white sugar | About 9 1/4 cups (2.2 L) | ComSaf 78 oz (about 9 3/4 cups) |
| 5 lb long-grain rice | About 11 1/2 cups (2.7 L) | More than one 78 oz jar |
| 5 lb all-purpose flour | About 19 cups (4.5 L) | More than one 4 qt jar (16 cups) |
For a full 5 lb bag of flour in one box, look for about 20 cups. Otherwise split it: one jar on the shelf, the rest sealed in the freezer. To start with brown sugar, the Rubbermaid 7.8 cup takes a whole 2 lb bag with room left over.
Keep pantry bugs out
An airtight container also keeps flour beetles and pantry moths out of the food, or locks them in if they came home in the bag. Utah State University Extension says insects "can chew through paper, plastic and foil bags," which is why the original bag is not enough.
- Freeze new flour or grains first if you have had bugs before. Utah State says 0°F (-18°C) or lower for 4 to 7 days; Kansas State says 3 days at 0°F for small packages like spices, 7 for larger ones; King Arthur says four days in the freezer works.
- Wash and dry the container before a refill, so old crumbs do not seed the new bag.
- Pick rigid over soft: all three Extension sources accept metal and rigid or heavy plastic; Kansas State and Illinois also name glass. None accepts a thin bag.
Freezing new flour for a few days at 0°F (-18°C) kills any eggs that came home in the bag.
Already seeing bugs? Our kitchen pest control guide walks through the clean-out.
Washing and care, per each listing
| Pick | Dishwasher | Other rules |
|---|---|---|
| Rubbermaid 7.8 cup | Yes, top rack | Freezer-safe. |
| ProKeeper 1.5 qt | Yes | 1-year limited warranty. |
| ComSaf 78 oz | Glass yes | Hand-dry the metal clamp. No microwave, no sudden temperature changes. |
| ComSaf 4 qt | Glass yes, bamboo lid no | Dry thoroughly. Lid not microwave-safe; seal not for liquids. |
Let every part dry fully before refilling: Domino says white sugar hardens with any moisture. Keeping bread too? See our bread box guide. For nuts and crackers you open less often, mason jar vacuum sealers pull the air out.
What we left out
- Vtopmart 78 oz glass jars: the same 4.5 by 10 inch size as the ComSaf pick, and the listing says "Hand Wash Only" in one field and calls the glass dishwasher-safe in another.
- Anchor Hocking Heritage Hill 1 gallon jars: a classic glass jar, but its listing lists its airtightness as "Vented" and says the jars "don't suction seal." Fine for cookies on a counter, not for brown sugar.
- OXO POP 1.1 qt: OXO sells this size for brown sugar, but at 1.04 L it only takes a 2 lb bag packed down, not poured loose. The listing also says Hand Wash Only in one field and dishwasher-safe in another.
Want lead and material details on storage containers for leftovers? See our non-toxic food storage containers guide.
Questions people ask
Can brown sugar be stored in a glass jar?
Yes. Domino asks for a rustproof container with a tight-fitting lid, and glass does not rust. Check the closure: a clamp jar has a metal wire, and ComSaf says to hand-dry its clamp after washing.
Which container is best for sugar?
Any airtight container sized to your bag. Domino says to store granulated sugar airtight "to keep sugar free flowing." A 4 lb bag is about 9 1/4 cups by King Arthur's weights, so a 78 oz jar fits it.
Does sugar have to be stored airtight?
If you want it to stay scoopable, yes. Domino says granulated sugar hardens when exposed to any moisture, and brown sugar hardens when its own moisture evaporates. A tight seal guards against both.
Should brown sugar go in the fridge?
No. Domino says not to store brown sugar in the refrigerator. In a very dry area, or for long storage, it says freezing is an option: thaw it and break up the clumps with a fork.
How long does brown sugar last?
Domino says brown sugar quality is best when used within six months of purchase and opening.
How do I store a 5 lb bag of flour?
It is about 19 cups by King Arthur's weights. Slide the whole bag into a container of about 20 cups, or split it: one jar out, the rest sealed in the freezer, which King Arthur recommends for long-term storage.
The verdict
For brown sugar, get the Rubbermaid Brilliance 7.8 cup, or the ProKeeper if your kitchen is dry and you want the terra cotta disc built in. For flour and white sugar in glass, get the ComSaf jars, size them to your bags, and dry the clamps before you close them.
See the Rubbermaid container on AmazonSee the ComSaf glass jars on Amazon
How we put this together
On 4 Nov 2026 we read each pick's Amazon US listing for material, capacity, care and stock, plus Domino, King Arthur and three Extension fact sheets. We did not handle these containers. Cup and pound figures are our math from King Arthur's weights. No brand saw this page before it went up.
Sources (opened 4 Nov 2026; product facts from each linked Amazon listing).
- Domino: How to Store Domino Brown Sugar
- Domino: How to Store Domino Granulated Sugar
- King Arthur Baking: How to store flour
- King Arthur Baking: Ingredient Weight Chart
- Utah State University Extension: Winter pests in your pantry (2013)
- Kansas State Research and Extension: Controlling Stored-Food Insects, MF-2270
- University of Illinois Extension: Pantry pests (PDF)
