Ninja Spice Grinder: Can It Actually Grind Coffee?

I get this question more than you'd expect. Someone already owns a Ninja blender or food processor, notices it came with a spice grinding attachment, and wonders if they can use it for coffee. Or they're eyeing the Ninja spice grinder accessory specifically because it's cheaper than a dedicated coffee grinder. The honest answer is yes, it can grind coffee beans, but the results have some serious limitations compared to a proper coffee grinder.

I've tested the Ninja spice grinder attachment with coffee beans alongside my regular burr grinder, and I'll share exactly what I found. I'll also explain why the grinding mechanism matters so much and when a Ninja spice grinder might actually be a reasonable option for coffee.

How the Ninja Spice Grinder Works

The Ninja spice grinding attachment uses a blade mechanism, similar to what you'd find in a cheap blade coffee grinder. A sharp metal blade spins at high speed inside a small cup, chopping whatever you put in it into smaller and smaller pieces. The longer you run it, the finer the result gets.

This is fundamentally different from how a burr coffee grinder works. Burr grinders crush beans between two abrasive surfaces set at a specific distance apart, producing a uniform particle size. Blade grinders, including the Ninja spice attachment, chop randomly, producing a mix of fine powder and larger chunks in the same batch.

For spices, this inconsistency doesn't matter much. Nobody cares if their ground cumin has a few larger flakes mixed in. For coffee, it matters a lot. Uneven particle sizes mean uneven extraction, which translates directly to a cup that tastes both bitter (from over-extracted fines) and sour (from under-extracted large chunks) at the same time.

What Happens When You Grind Coffee in a Ninja Spice Grinder

I ran three batches of the same medium-roast beans through my Ninja spice grinder attachment at different pulse times to see what each produced.

Quick Pulse (3-5 seconds)

Short pulses produced a very coarse, uneven grind. Some chunks were nearly whole bean halves, while other particles were already quite fine. The spread was too wide for any brewing method to work well. I tried it in a French press, and the cup was thin and under-extracted because most of the coffee was too coarse.

Medium Pulse (10-15 seconds)

At 10-15 seconds of pulsing (in 2-3 second bursts with shaking in between), the grind looked roughly like a drip coffee grind. The consistency was still uneven, with visible fine powder mixed in with medium particles. I brewed this in an auto-drip machine, and the coffee tasted okay. Not great, but noticeably better than pre-ground coffee from a can.

Long Grind (20-30 seconds)

Running the Ninja for 20+ seconds continuous produced a very fine grind approaching Turkish coffee territory, but with so much heat that I could feel the cup was warm to the touch. Heat during grinding degrades flavor compounds in coffee, so this approach sacrifices some taste quality even before you brew.

Ninja Spice Grinder vs. A Proper Coffee Grinder

Let me put this comparison in concrete terms using the same beans, same water, same brew method.

I ground 20 grams of a Colombian medium roast in both my Ninja spice attachment and my Baratza Encore (a basic burr grinder) at a medium pour over setting. I brewed both with a Melitta dripper using 320 grams of 200°F water.

The Ninja cup was flat, slightly bitter on the finish, and lacked the brightness and sweetness I know those beans can produce. The brew time was inconsistent because the fine powder clogged the filter early, causing a slow drawdown.

The Baratza cup was clean, bright, with a caramel sweetness and a smooth finish. The brew time was predictable at about 3 minutes and 15 seconds.

The difference was obvious even to my wife, who doesn't consider herself a coffee person. She described the Ninja cup as "strong but not as good" and the Baratza cup as "smoother."

This isn't surprising. Every coffee professional will tell you the same thing. A burr grinder produces better coffee than a blade grinder. The Ninja spice attachment is a blade grinder. If you want the full range of options for dedicated coffee grinders, our best coffee grinder guide covers picks at every price point.

When a Ninja Spice Grinder Actually Makes Sense

I don't want to be completely dismissive here. There are situations where using a Ninja spice grinder for coffee is a perfectly reasonable choice.

If you already own one and you're currently buying pre-ground coffee, grinding your own beans with the Ninja will produce a noticeable improvement. Fresh-ground coffee, even inconsistently ground, tastes better than coffee that was ground weeks ago at a factory. The freshness advantage outweighs the consistency disadvantage.

If you're traveling and the only tool available is a Ninja blender with the spice attachment, go for it. Bad grinding method with good beans still beats no fresh coffee.

If you're on an extremely tight budget and can't afford even a $15-20 manual burr grinder, using what you have is better than nothing. But honestly, a manual burr grinder like the JavaPresse or a basic Hario is so inexpensive that I'd suggest buying one before spending money on whole beans. The investment pays for itself immediately in better taste.

Tips for Better Coffee from a Ninja Spice Grinder

If you do use the Ninja for coffee, these tricks will help you get the best possible results.

Pulse, don't hold. Use 2-3 second bursts instead of continuous grinding. Shake the cup between pulses to redistribute the beans. This gives you a slightly more even grind than continuous operation.

Grind in small batches. Fill the cup only about one-third full. Overloading the cup means the blade can't reach all the beans, which creates more unevenness. For a typical 20-gram dose, this shouldn't be an issue since it's a small amount.

Sift the grounds. This sounds excessive, but running your grounds through a fine mesh strainer separates the powder-fine particles from the medium grounds. Brew with the medium grounds and discard or compost the fines. Your cup will taste significantly better.

Clean the cup after every use. Coffee oils go rancid quickly and will make future grinds taste stale. If you also use the cup for spices, clean it thoroughly between uses or your coffee will taste like cumin or cinnamon.

Don't grind more than you need for one session. Since you can't seal the Ninja cup airtight, ground coffee exposed to air will go stale within hours. Grind right before brewing.

Should You Buy a Ninja Spice Grinder Specifically for Coffee?

No. If you're buying something new specifically for coffee grinding, a dedicated coffee grinder is always the better choice. A manual burr grinder costs $20-40 and produces significantly better results. An entry-level electric burr grinder like the Bodum Bistro runs about $70-100 and outperforms the Ninja by a wide margin.

The Ninja spice grinder is a useful attachment for its intended purpose: grinding spices, nuts, and small dry ingredients. It can grind coffee in a pinch, but spending even $20 on a basic burr grinder will make a bigger difference in your cup quality than any other upgrade you could make. For top picks across all categories, check out our top coffee grinder roundup.

FAQ

Will grinding coffee beans damage my Ninja spice grinder?

No. Coffee beans are softer than many spices and won't damage the blade or motor. However, grinding coffee regularly will leave oil residue that needs cleaning, and the plastic cup may absorb coffee odors over time.

How fine can the Ninja spice grinder grind coffee?

With extended grinding (20-30+ seconds), you can achieve a very fine, almost powder-like consistency. However, the heat generated during prolonged grinding can harm flavor, and the grind will still contain uneven particles. It can get close to a Moka pot fineness, but the inconsistency makes it unsuitable for true espresso.

Can I use the Ninja spice grinder for cold brew coffee?

Actually, yes. Cold brew is one of the most forgiving methods when it comes to grind consistency. A coarse, uneven grind from the Ninja (short 3-5 second pulses) works fine for cold brew since the long steeping time (12-24 hours) extracts flavor regardless of particle uniformity. This is probably the best coffee application for the Ninja spice grinder.

Is it better to use the Ninja or buy pre-ground coffee?

Grinding your own beans with the Ninja is better than buying pre-ground, assuming you're buying quality whole beans. Freshness matters more than grind consistency for overall cup quality. A fresh but unevenly ground coffee beats a perfectly ground coffee that's been sitting in a bag for three weeks.

My Take

Use your Ninja spice grinder for coffee if you already have one and you're in a bind. It works. But if you're serious about your morning cup at all, spend $25-40 on a basic burr grinder and save the Ninja for what it was designed to do. The difference in your cup will be immediate and obvious.