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ATLAS DIRECTORY · Microwave · store label

Kirkland Signature logoKirkland Signature

Costco's warehouse box. Other testers keep putting it first.

Score
—
Kernel
commodity microwave
Origin
United States
Best for
warehouse butter bag
Buy
Costco box

Last popped / last updated Aug 2026

What holds

  • Wins microwave tests we opened (Allrecipes, Parade, Serious Eats)
  • Honest warehouse price

What doesn't

  • Not a farm
  • Co-packer unpublished — we do not guess

The kernel

Kirkland Signature is Costco's name on a microwave bag, usually Movie Theater Butter in a warehouse box. Parade's 14-brand test put it first. Allrecipes and Delish said the same in 2026 SERP writeups. Daily Herald / Washington Post tasters were cooler: a tie with Aldi's Clancy's at 46, fluffy, not much but butter.

The pot

The pot is a club microwave. You buy a 44-bag box, not a brand story. This is not a farm and not an independent company. Manufacturer is unpublished on the pages we opened.

Hulls

Hulls are store-label yellow. Say the quiet part: it is a store brand. That is not a slur. It is the file.

Company

A warehouse label that keeps winning microwave roundups. Say so. It is not a farm.

Parent
Costco store label. Not an independent popcorn company. Manufacturer is not printed as a public brand fact we could confirm on a page opened here.
HQ / farm
Costco Wholesale. Sold in the warehouse, not as a farm brand.

Sources: Parade 14-brand microwave test · Daily Herald / WaPo test

Where to buy

  • Costco. The 44-bag Movie Theater Butter box is the SKU taste tests keep buying.

No affiliate hop. No Stripe. Official and search links only.

How we score

Directory listing. Unscored until Barron tastes it. Other testers' rankings are cited, not copied. Tiny But Mighty stays #01. Farm varieties outrank flavor labs. Read the method in the how we score guide and on the about page.

The record

Unscored. On the map because the box dominates the tests. The door is Costco.

Directory listing. A Costco label that keeps winning microwave roundups. Say the quiet part: it is a store brand.

Brand site: costco.com.