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True 190°F Simmer. Pure Lead-Free Stoneware.

Cosari HearthStone 4Q

Most modern slow cookers secretly boil at 212°F on Low—turning good beef into dry stringy leather.

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  • Calibrated 190°F Low / 205°F High Simmer —
  • 100% Lead, Cadmium & PFAS-Free — 6.2 mm
  • Tailored 4-Qt Oval Footprint — fits a 4
  • Silent Auto-Warm Shift & Dishwasher Safe — holds
Cosari HearthStone 4Q
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Engineered for Collagen-Melting Precision, Not Shortcuts

Every detail solves the overheating, toxic-glaze worries, and cabinet clutter of big-box slow cookers.

True 190°F Digital Simmer

Solid-state NTC thermistor holds Low right at 190°F (±4°F) so tough connective tissue melts into rich gelatin without squeezing meat fibers dry.

0.00 ppm Lead-Free Stoneware

Thick 6.2 mm vitrified mineral ceramic pot contains zero detectable lead or cadmium and zero flaking PTFE/PFAS synthetic coatings.

Silent 165°F Auto-Warm

Set cook times from 30 minutes to 20 hours; when the clock hits zero, heat steps smoothly down to 165°F for up to 6 hours with zero frantic beeping.

3-Minute Soak & Dishwasher Clean

Non-porous obsidian ceramic glaze releases baked-on reductions effortlessly with warm soapy water or drops upright into your dishwasher rack.

Why HearthStone Braises Taste Like a 5-Hour French Dutch Oven

1. 360° Wraparound Stoneware Thermal Mass

1. 360° Wraparound Stoneware Thermal Mass

Unlike pressure cookers that scorch food from a flat bottom metal plate, our wraparound side element cradles 6.2 mm kiln-fired ceramic walls in even radiant heat from bottom to rim.

2. Three-Tap NTC Temperature Control

2. Three-Tap NTC Temperature Control

Select Low (190°F), High (205°F), or Warm (165°F) in 30-minute timer increments on the minimalist brushed-stainless fascia—no confusing 14-button menus.

3. Recessed Vapor-Lock Glass Lid

3. Recessed Vapor-Lock Glass Lid

The stainless-trimmed tempered glass lid seats deep inside the stoneware lip, condensing natural moisture pearls right back over your short ribs so sauces never boil down.

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Cosari HearthStone 4Q

Calibrated 190°F True-Simmer Digital Slow Cooker • 100% Lead-Free 4-Qt Vitrified Stoneware

Backed by our 30-Day Money-Back Trial & Full 2-Year Cosari Warranty.

$89.99 $179.99 Free Tracked Shipping (5–7 Days) Included

In Stock: Delivers in 5–7 Business Days. Free insured US delivery with tracking.

30-Day Money-Back Guarantee plus a full 2-Year Warranty.

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Description

Built for 2-to-5-Person Households: Cavernous 6.5-quart tubs force everyday meals into a thin layer that burns. Our 4.0-quart (3.8L) oval fits a 4 lb chuck roast, 4.5 lb whole chicken, or 5 hearty bowls of chili while tucking neatly under 18-inch upper cabinets.

Oven-to-Table Culinary Versatility: Lift the glossy black stoneware vessel straight from the matte-black & 304 stainless base into a 400°F oven to brown Gruyère toppings, then set it right on a dining table trivet.

Two Honest Caveats Before You Order: First, if you routinely cook 10-pound pork butts for 14-person potlucks, choose an 8-quart commercial tub instead. Second, genuine kiln-fired stoneware is 400°F oven-safe, never for open gas stovetop flames.

5–7 Day Shipping & 30-Day Returns

Free 5–7 Day US Shipping: Every order ships free with full tracking and delivers in 5 to 7 business days.

30-Day Trial: Try it at home for 30 days risk-free. Need help? Email us anytime at support@buycosari.com.

2-Year Warranty: If anything goes wrong within 2 years, we replace it free of charge or refund your order in full.

Why Choose the Cosari HearthStone 4Q?

Cosari HearthStone 4Q Detail

Wraparound 210W Radiant Element

Gentle side-wall heating eliminates bottom hot spots while sipping less electricity over 8 hours than a desktop monitor.

Compact Architectural Proportions

Measuring just 13.8" W × 10.4" D × 9.6" H, it looks tailored on stone counters and slides onto standard 13-inch pantry shelves.

2-Year Stoneware & Base Protection

Protected by our 30-day money-back trial plus a full 2-year replacement warranty covering both digital electronics and normal-use ceramic heat integrity.

Cosari HearthStone 4Q vs. Ordinary Alternatives

Cosari HearthStone 4QStandard Competitors

FeatureCosari HearthStone 4QStandard Competitors
Actual 'Low' Cooking TempCalibrated 190°F (±4°F) True SimmerUnregulated 212°F Meat-Drying Boil
Cooking Surface Purity6.2 mm 0.00 ppm Lead-Free StonewarePeeling PTFE Nonstick or Mystery Glaze
Heat Distribution360° Side-Wall Ceramic RadianceBottom-Only Metal Plate Scorching
End-of-Cycle ProtectionSilent 6-Hr Auto-Shift to 165°F WarmKeeps Boiling or Loud Endless Beeping
Everyday Counter FitTailored 4-Qt Oval (Fits 4 lb Roast)Bulky 6.5-Qt Vat That Overheats Small Meals
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What's Included

In the Box
  • 1 × Cosari HearthStone 4Q Matte-Black & Brushed 304 Stainless Heating Base (120V US Plug)
  • 1 × Removable 4.0-Quart Lead-Free Glazed Black Stoneware Oval Pot
  • 1 × Stainless-Rimmed Tempered Glass Lid with Cool-Touch Handle
  • 1 × Printed Quick-Start & Calibrated Braising Time Guide
Technical Specifications
  • Capacity: 4.0 Quarts (3.8 Liters) Oval — fits up to a 4 lb roast or 4.5 lb whole chicken
  • Calibrated Temp Modes: Low 190°F (±4°F) / High 205°F / Auto-Warm 165°F
  • Programmable Timer: 30-minute increments from 0.5 hours to 20.0 hours (plus 6-hr Auto-Warm)
  • Inner Vessel Material: 6.2 mm kiln-fired vitrified stoneware (0.00 ppm lead & cadmium, PFAS/PTFE-free)
  • Exterior Housing: Brushed 304 stainless steel wrap with satin matte-black collar & cool-touch handles
  • Oven & Dishwasher Rating: Ceramic pot oven-safe to 400°F; pot & tempered glass lid dishwasher safe
  • Dimensions & Weight: 13.8" W × 10.4" D × 9.6" H (9.4 lbs total with stoneware seated)
  • Electrical Rating: 120V ~ 60Hz, 210W energy-efficient wraparound element, 36-inch US polarized cord
Care & Safety
  • Allow the stoneware ceramic pot to cool before submerging in cold water to prevent thermal shock; wipe baked-on sauces after a 3-minute warm soapy soak or load directly into the dishwasher.
  • Stoneware pot is safe for ovens up to 400°F; never place ceramic stoneware directly over gas flames, electric coils, or induction stovetops. Wipe the stainless exterior base with a damp microfiber cloth.
  • Backed by our 30-Day Money-Back Guarantee & 2-Year Warranty
  • Customer Support: support@buycosari.com
In the Box Cosari HearthStone 4Q

Spoon-Tender Weeknight Dinner in 3 Effortless Steps

Swipe left for steps 2 and 3

  1. 1. Load the Stoneware
    1

    1. Load the Stoneware

    Nestle your seasoned roast, aromatics, and broth into the removable lead-free ceramic pot and seat it cleanly inside the stainless base.

  2. 2. Tap Low & Walk Out
    2

    2. Tap Low & Walk Out

    Place the tempered glass lid flush, set your timer in 30-minute steps, and head to work—it switches silently to 165°F Warm the moment it finishes.

  3. 3. Shred & Serve Table-Ready
    3

    3. Shred & Serve Table-Ready

    Lift the glossy obsidian stoneware pot straight onto a dining trivet at 6:00 PM and pull apart juicy, velvety meat with two forks.

Verified Customer Reviews

What 200+ Verified Buyers Say About the Cosari HearthStone 4Q

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4.8
Based on 247 verified reviews
5 Stars
212
4 Stars
25
3 Stars
7
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1 Star
1
97% of buyers recommend the Cosari HearthStone 4Q
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✓ Verified Purchase
Rachel T.Verified Purchase • 6 days ago

Finally simmers like my mom's 1995 stoneware pot instead of boiling!

I was ready to give up on modern slow cookers altogether because my last two name-brand ones boiled like a volcano even on Low and charred chili to the sides in four hours. Plugged the HearthStone 4Q in at 10 AM with chicken tinga, came into the kitchen at 6 PM, and saw tiny, lazy bubbles under the glass lid instead of a rolling boil. The meat stayed ridiculously juicy instead of stringy. Worth every penny.

Verified Purchase · Columbus, OH · Cosari HearthStone 4Q

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Mark & Julie D.Verified Purchase • 2 weeks ago

Fits a 4-lb chuck roast like a glove and goes straight to the table

Six-quart cookers are way too cavernous for two or three people—unless you fill them halfway, food spreads out too thin and dries right out. This 4-quart oval nestled a 3.8-pound chuck roast over onions and carrots like it was custom-tailored. Best part is lifting the glossy black stoneware insert straight out of the base onto a cork trivet on our dining table—it looks like a $200 piece of French ceramic cookware.

Verified Purchase · Naperville, IL · Cosari HearthStone 4Q

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Lauren K.Verified Purchase • 2 weeks ago

Zero nonstick coatings flaking into tomato sauce or bone broth

Once I started reading about PTFE nonstick coatings bubbling after 8 hours of simmering acidic marinara, I tossed our aluminum multi-cooker insert immediately. Having independently lab-verified, 100% lead-free vitrified stoneware gives me complete peace of mind when making overnight beef bone broth for my toddlers. Heavy, thick glaze with zero hairline crazing.

Verified Purchase · Austin, TX · Cosari HearthStone 4Q

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Greg H.Verified Purchase • 3 weeks ago

Blew my Instant Pot's slow-cook mode out of the water

I fell for the myth that a pressure cooker could replace a real slow cooker. Dead wrong—mine only heated from a thin metal plate on the bottom, leaving stew burnt underneath and half-raw on top. The wrap-around heat and thick stoneware on the Cosari hold an actual 190°F braise. Made short ribs Sunday and my wife went back for thirds.

Verified Purchase · Tacoma, WA · Cosari HearthStone 4Q

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Denise W.Verified Purchase • 3 weeks ago

Quiet switch to Auto-Warm when commuter traffic runs late

All I wanted was a reliable digital timer that shifts to Warm without screaming with a 90-decibel beep for ten minutes while the dog barks. When soccer practice or I-40 traffic delays us by 45 minutes, dinner sits safely at a gentle warm temp without drying out. Plus the matte black and brushed steel looks sleek on the counter.

Verified Purchase · Raleigh, NC · Cosari HearthStone 4Q

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kevin_m82Verified Purchase • 1 month ago

Checked it with my instant-read probe—spot on 191°F on Low

I'm a barbecue nerd so I know the entire science of collagen breakdown happens between 185°F and 195°F, whereas boiling at 212°F wrings muscle fibers dry. Tested water and then pork shoulder in this unit after 6 hours on Low and my digital probe read 191°F dead center. Pulled pork came out silky instead of mushy.

Verified Purchase · Omaha, NE · Cosari HearthStone 4Q

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Patricia S.Verified Purchase • 1 month ago

Two-minute cleanup even after game-day queso

Used this for warm chorizo queso dip during football Sunday and braced myself for a nightmare scrub session. Let the ceramic pot cool down, filled it with warm water and a drop of Dawn while we cleaned up plates, and wiped every bit of baked cheese right off with a soft sponge. Slides right onto my pantry shelf without hogging half the cabinet.

Verified Purchase · Sarasota, FL · Cosari HearthStone 4Q

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Brian C.Verified Purchase • 1 month ago

Phenomenal braiser for 2 to 4 people (just size your cuts right)

Knocking off half a star if I could just to note you obviously aren't fitting an 8-pound bone-in holiday ham in a 4-quart oval. That said, for everyday 3-to-4-pound chuck roasts, whole 4-pound chickens, French onion soup, and steel-cut oats for a family of four, the temperature control is leagues better than our giant 7-quart ever was.

Verified Purchase · Pittsburgh, PA · Cosari HearthStone 4Q

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Hannah R.Verified Purchase • 5 weeks ago

Converted my slow-cooker-hating husband on night one

My husband swore for years that he hated slow cooker dinners because everything tasted 'watery and dry at the exact same time.' Turns out our old cooker was boiling all the juice out of the beef into the broth! Made Tuscan white bean and rosemary lamb shanks in the HearthStone and the meat cut with a fork.

Verified Purchase · Boise, ID · Cosari HearthStone 4Q

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Diane L.Verified Purchase • 6 weeks ago

Sturdy cool-touch handles and intuitive buttons

Bought one for myself and came back for a second one at 50% off for my daughter's apartment. No confusing 18-button spaceship menu—just set Low or High and tap your hours. The side handles stay cool enough to reposition it on the counter mid-cook, and the glass lid sits snug without rattling.

Verified Purchase · Hartford, CT · Cosari HearthStone 4Q

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Frequently Asked Questions

Does the 'Low' setting actually simmer around 190°F instead of boiling at 212°F?

Yes. Unlike budget bimetallic slow cookers wired to hit 212°F on every setting, the Cosari HearthStone 4Q uses a calibrated NTC digital thermistor that holds Low at 190°F (±4°F), High at 205°F, and Auto-Warm at a gentle, food-safe 165°F.

Is the black ceramic glaze tested free of lead, cadmium, and PFAS/PTFE?

100%. The 6.2 mm removable inner pot is crafted from high-density kiln-fired vitrified mineral stoneware verified to 0.00 ppm detectable lead and cadmium under FDA CPG 7117.06/07 standards, with zero synthetic PTFE, PFOA, or PFAS nonstick coatings.

What exact roast or chicken size fits inside the 4-quart oval pot?

The tailored oval geometry comfortably fits up to a 4-pound tied beef chuck roast or pork shoulder nestled over onions and carrots, a whole 4.5-pound chicken, or up to 5 generous adult servings of chili, curry, or bone broth.

Does it automatically switch to Warm when the timer finishes?

Yes. Once your programmed cook time (adjustable in 30-minute increments from 0.5 to 20 hours) reaches zero, the unit silently shifts down to 165°F Auto-Warm for up to 6 hours without loud repetitive beeping.

Are the stoneware pot and glass lid dishwasher and oven safe?

Both the removable glazed stoneware insert and the stainless-rimmed tempered glass lid are dishwasher safe. The stoneware ceramic pot is also oven safe up to 400°F for melting cheese or crisping toppings (do not place stoneware over open stovetop burners, and keep the glass lid out of the broiler).

What are the US electrical specs, and how does the 30-day guarantee work?

It uses a standard 120V / 60Hz US polarized plug with an energy-efficient 210W wraparound heating element. Cook in your own kitchen for 30 full days—if your roasts aren't noticeably juicier than your old slow cooker, return it for a full refund, plus enjoy 2-year warranty protection on both the heating base and stoneware pot.

Cosari HearthStone 4QIn Stock · 30-Day Trial
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