Comstock-Castle 2923SF 23" Flat-Bottom Doughnut Fryer, Countertop Gas, 50,000 BTU
Comstock-Castle 2923SF 23-Inch Flat-Bottom Doughnut Fryer (Countertop Gas, 20-24 lb Oil Capacity, 50,000 BTU)
The Comstock-Castle 2923SF is a 23-inch countertop gas doughnut fryer built around a wide flat-bottom stainless steel tank engineered for traditional doughnut and funnel cake frying. Where deep fryer baskets submerge product in tall narrow tanks, a doughnut fryer floats product on a shallow oil bath so doughnuts and funnel cakes cook on one side, get flipped by hand once the bottom is golden, then cook on the second side before being lifted out with a screen or skimmer. This is how doughnuts have been made in American bakeries for over a hundred years and the 2923SF tank geometry is purpose-built for that workflow.
The tank interior measures 20.25 inches wide by 21 inches front-to-back with a 4.25 inch oil depth, which holds roughly 2.5 to 3 gallons of frying shortening or oil (20 to 24 pounds). That capacity is the sweet spot for a small to mid-volume doughnut shop, a bakery adding cake doughnuts and crullers to a morning case, a fair or festival concession running fresh-made mini-doughnuts, a food truck or trailer running a doughnut menu, or a coffee shop and ice cream parlor adding hot doughnuts to a counter program. The 50,000 BTU long-life cast iron H-pattern burners feed heat into a V-shaped tank base that directs flame around the oil for fast recovery between batches, and a snap-action thermostat keeps oil temperature locked at the doughnut frying setpoint without overshoot.
Comstock-Castle has built fryers in Quincy, Illinois since 1838 and is America's oldest stove company. The 2923SF is NSF listed for commercial foodservice use and UL listed for commercial gas equipment.
Best Use Cases for the 2923SF Doughnut Fryer
- Small to mid-volume doughnut shops running cake doughnuts, raised yeast doughnuts, and crullers
- Bakeries adding a fresh-made doughnut case to a morning pastry program
- Coffee shops, cafes, and espresso bars adding hot doughnuts to a counter program
- Ice cream parlors and dessert shops adding warm doughnuts as a counter draw
- Mini-doughnut programs at fairs, festivals, county fairs, state fairs, and event concessions
- Funnel cake stands at fairs, carnivals, theme parks, and outdoor events
- Food trucks and trailers running a doughnut or funnel cake menu under a Type 1 hood
- Cider mills, orchards, and pumpkin patches running seasonal cider doughnut programs
- School concessions, sports stadium kiosks, and university food service running doughnut or funnel cake stations
- Hotel breakfast and brunch programs adding fresh doughnuts to a continental setup
- Doughnut wholesalers, commissary kitchens, and ghost kitchens building doughnut SKUs for delivery channels
How a Flat-Bottom Doughnut Fryer Differs From a Deep Fryer
A commercial deep fryer is built around vertical tank geometry. Product sits in a wire basket and is fully submerged in 30 to 80 pounds of oil. Recovery is measured by how fast the burner reheats a deep oil column after a basket of frozen fries drops the temperature. Doughnuts are a completely different cooking problem. Doughnuts are made from a buoyant dough that wants to float, they cook from the bottom up on one side then need to be flipped, and they pick up dramatic color shifts within seconds of flipping. A deep fryer tank traps doughnuts against the basket and the side walls, prevents the operator from flipping individual doughnuts, and burns the bottoms because the oil is too deep to monitor.
A flat-bottom doughnut fryer like the 2923SF solves that. The shallow 4.25 inch oil depth lets doughnuts float on the surface with the operator's screen or skimmer right at hand. The 20.25 by 21 inch flat-bottom tank gives a single doughnut maker enough surface area to float roughly six to ten doughnuts at a time depending on size, flip each one individually with a wooden dowel or screen, and pull them out the moment the second side is golden. The V-shaped tank base concentrates burner heat at the center of the oil pool, which prevents cold spots at the perimeter where doughnuts tend to drift. Funnel cakes work the same way: the operator pours batter through a funnel into the hot oil in a spiral pattern, lets the cake set on one side, flips it once with a screen, then lifts the finished cake out to drain. Both products need the flat-bottom shallow tank to cook correctly.
Target Oil Temperature, Recovery, and Setpoint
Most doughnut programs run at 360 to 375 degrees Fahrenheit. Cake doughnuts and crullers are typically fried at 365 to 375 degrees F. Raised yeast doughnuts are fried at 360 to 365 degrees F. Mini-doughnuts and donut holes are fried at 370 to 375 degrees F because they cook in 30 to 60 seconds per side and need a slightly hotter oil to set the exterior fast. Funnel cakes are fried at 350 to 370 degrees F depending on batter thickness. The 2923SF snap-action thermostat is rated for the full doughnut frying range and holds the setpoint within a few degrees during normal service.
Recovery is the key performance metric for any doughnut fryer. When a fresh batch of cool doughnuts drops onto hot oil, the surface temperature drops as the doughnuts absorb thermal energy. If the burner cannot recover fast enough, the second and third batches go in below setpoint, the doughnuts soak oil instead of frying, and the finished product comes out greasy. The 50,000 BTU output paired with the 20 to 24 pound oil capacity gives the 2923SF a strong BTU-to-oil ratio (roughly 2,200 BTU per pound of oil) so recovery between standard batches stays inside the 60 to 90 second window most doughnut programs target.
Loading Patterns, Flipping, and Batch Size
Most operators load the 2923SF in two rows of three to four doughnuts each, working front to back. Loading order matters: start at the back of the tank and work forward so the operator's hand and dowel do not need to cross over hot frying doughnuts to reach the next loading slot. The standard tool is a wooden dowel about half an inch in diameter and 12 to 14 inches long. Dowels do not transfer heat the way metal does, do not scratch the stainless tank, and let the operator flip doughnuts with a smooth roll instead of a slap that splashes oil.
Cake doughnuts typically cook 60 to 75 seconds per side at 370 degrees F. Raised yeast doughnuts typically cook 50 to 60 seconds per side at 360 to 365 degrees F. Crullers cook 45 to 60 seconds per side at 370 to 375 degrees F. Mini-doughnuts and donut holes cook 30 to 60 seconds total and are usually turned with a screen rather than flipped individually. Flipping is by feel: the operator watches for the bottom edge of each doughnut to turn from pale to deep golden, then rolls the doughnut over with the dowel. After the second side hits the same deep golden color, the doughnut is lifted out with a long-handled screen or skimmer and laid on a draining rack or pan over absorbent paper.
Oil Selection and Tank Fill
The 2923SF tank is filled to 2.5 to 3 gallons (20 to 24 pounds) of frying shortening or oil. Most doughnut shops run solid all-purpose vegetable shortening that solidifies at room temperature, which is the traditional doughnut shop standard and produces the classic crisp exterior with a tender crumb interior. Liquid frying oils (high-oleic canola, sunflower, or palm-blend doughnut frying oils) are also commonly used and produce a slightly lighter texture. Whichever the operator chooses, the tank should be filled to the marked oil level line and topped off as oil is absorbed by the product during service. Cake doughnuts absorb 25 to 30 percent of their weight in oil during frying, raised doughnuts absorb 15 to 25 percent, and that absorbed oil needs to be replaced from the fresh-oil reservoir to keep the tank at fill level.
If running solid shortening, melt the shortening at low temperature setting before bringing oil up to frying temperature. Cold shortening on a hot burner can scorch on the tank bottom and develop off flavors. The standing pilot can be used to warm shortening slowly overnight in some installs, but most operators prefer to start the burner at low setting and ramp up over 15 to 20 minutes from solid shortening.
Oil Management, Glaze Runoff, and Cleaning
Doughnut oil takes on a unique load profile compared to french fry or chicken oil. Glaze, cinnamon sugar, and powdered sugar from finished doughnuts sometimes drift back into the tank when operators set draining doughnuts too close to the fryer. Crumbs from cake doughnut batter break off during the flip and accumulate on the tank bottom. Burned crumbs are the number one cause of off flavors in doughnut oil. Skim the surface of the oil every 30 to 60 minutes during service with a fine-mesh skimmer to remove floating crumbs and any sugar that has drifted in. Filter the oil at the end of every service day through a coffee filter, doughnut oil filter cone, or portable filter unit.
The angled tank bottom with a 3/4 inch front gate valve makes end-of-day draining straightforward. Position a portable oil caddy or filter unit under the gate valve, open the valve, and let the oil drain into the caddy for filtering. Once the tank is empty, wipe the interior with a damp cloth (never use harsh detergents on a doughnut fryer tank because residue can carry into the next day's oil), reseat the valve, and refill with filtered oil. Replace oil entirely when free fatty acid level exceeds 2.0 percent, when smoke point drops below 350 degrees F, or when oil color turns dark amber and doughnuts start to taste like the oil rather than the dough. Most doughnut shops replace oil every 7 to 14 days depending on volume.
Natural Gas and Propane Configuration
The 2923SF ships factory-set for natural gas at 4 inches water column manifold pressure and is easily convertible to propane at 10 inches water column. The manifold is 3/4 inch NPT and the gas connection is at the rear of the unit. Propane conversion requires the standard burner orifice swap and regulator adjustment performed by a certified gas technician. Specify NG or LP at order if a factory propane setup is preferred over field conversion.
Construction, Burners, and Controls
The 2923SF tank, front, and side panels are 100 percent stainless steel with aluminized inner framing. Double-wall construction with heavy insulation combined with the special flue design produces cooler exterior operation than single-wall countertop fryers, which matters when the unit is installed near operators who lean in to flip doughnuts. The hinged front door panel protects the gas controls, standing pilot, and burner valves from spills and cleaning splash. The 4 inch adjustable stainless steel legs let the unit level on an uneven prep table or commercial worktable.
Burners are long-life cast iron H-pattern burners. Cast iron burner construction is the heavy-duty standard for commercial gas fryers because cast iron survives thermal cycling, splash, and cleaning chemicals that erode lighter sheet-steel burners over time. The H-pattern flame distribution combined with the V-shaped tank base produces even heating across the full flat-bottom tank without hot spots that would burn the bottoms of doughnuts floating directly above the burner.
Controls are a snap-action thermostat for fast temperature recovery, 100 percent gas safety shutoff that closes the main burner valve if the pilot flame is lost, a separate high-limit safety control for backup over-temperature protection, automatic standing pilot ignition, and brass burner valves. All controls are factory tested and confirmed in working order before the unit ships.
Specifications
| Specification | Value |
|---|---|
| Model Number | 2923SF |
| Manufacturer | Comstock-Castle Stove Co. (Quincy, IL, est. 1838) |
| Type | Flat-bottom doughnut and funnel cake fryer, countertop, gas |
| Overall Width | 23 inches |
| Overall Depth | 28.5 inches |
| Overall Height | 20 inches |
| Tank Interior Width | 20.25 inches |
| Tank Interior Length (front to back) | 21 inches |
| Tank Interior Depth (oil level) | 4.25 inches |
| Oil Capacity | 2.5 to 3 gallons (20 to 24 lbs) |
| Total BTU | 50,000 |
| BTU per Pound of Oil | Approximately 2,200 |
| Gas Type | Natural gas factory-set, easily convertible to propane |
| Natural Gas Manifold Pressure | 4 inches water column |
| Propane Manifold Pressure | 10 inches water column |
| Gas Connection | 3/4 inch NPT, rear of unit |
| Burners | Cast iron, H-pattern, long-life |
| Tank Base | V-shaped for directed heat distribution |
| Thermostat | Snap-action for fast recovery |
| Safety Controls | 100 percent gas safety shutoff, high-limit backup, standing pilot |
| Burner Valves | Brass |
| Tank Drain | 3/4 inch front gate valve, angled tank bottom |
| Construction | Stainless steel finish, aluminized inner framing, double-wall insulated |
| Legs | 4-inch adjustable stainless steel |
| Approximate Ship Weight | 125 lbs |
| Installation Clearance (non-combustible) | 2 inches sides, 6 inches rear |
| Installation Clearance (combustible) | 6 inches sides, 6 inches rear |
| Certifications | NSF, UL |
Installation Requirements
The 2923SF is a commercial gas appliance and must be installed under a Type 1 commercial hood with a UL 300 wet-chemical fire suppression system in any indoor commercial kitchen. Gas line sizing should match the 50,000 BTU input demand plus headroom for any other appliances on the same gas branch. The 3/4 inch NPT manifold connection is at the rear of the unit, so plan gas plumbing to land at the rear wall with a manual shutoff valve and dirt pocket within reach of the unit for service access.
Installation Checklist
- Type 1 commercial hood capture above the fryer, sized to manufacturer specifications for the local jurisdiction
- UL 300 wet-chemical fire suppression system rated for the hood configuration
- Gas branch sized for 50,000 BTU plus all other appliances on the same branch
- 3/4 inch NPT manual shutoff valve at the wall within reach of the unit
- Dirt pocket and union fitting at the rear gas connection for service access
- Gas leak test completed by the installer before lighting the pilot
- Manifold pressure verified at 4 inches WC for natural gas or 10 inches WC for propane
- Non-combustible countertop or worktable rated for the heat load
- 2 inch side and 6 inch rear clearance for non-combustible surfaces, 6 inch side and 6 inch rear for combustible
- Floor sink or oil-disposal access for end-of-day draining
- Doughnut draining rack or absorbent-paper-lined pan staged adjacent to the unit
Doughnut Workflow Layout
- Proofer or batter station on one side of the fryer to stage raw product
- Doughnut maker positioned in front of the fryer with a wooden dowel and screen at hand
- Draining rack on the opposite side of the fryer for finished doughnuts
- Glazing or sugaring station downstream of the draining rack
- Display case or boxing station downstream of the glazing station
- Filter caddy or portable filter unit stored within reach for end-of-day oil filtering
Frequently Asked Questions
What is the 2923SF designed to fry?
The 2923SF is a flat-bottom doughnut fryer designed for traditional American doughnut frying including cake doughnuts, raised yeast doughnuts, crullers, mini-doughnuts, doughnut holes, and cider doughnuts. The same flat-bottom tank also fries funnel cakes, fritters, beignets, sopapillas, churros, and similar batter-fried products.
How is this different from a deep fryer?
A deep fryer uses a tall narrow tank with wire baskets that fully submerge product. A doughnut fryer uses a shallow flat-bottom tank that floats product on the oil surface so the operator can flip each piece by hand. Doughnuts and funnel cakes need the flat-bottom geometry to cook correctly. A deep fryer cannot replace a doughnut fryer for these products.
How many doughnuts can the 2923SF fry at one time?
Approximately six to ten doughnuts at a time on the 20.25 by 21 inch flat-bottom tank, depending on doughnut diameter. Standard 3.5 to 4 inch ring doughnuts fit roughly two rows of three. Mini-doughnuts and donut holes can be staged in larger batches because they cook in 30 to 60 seconds and clear the tank fast.
What oil temperature should I use?
Cake doughnuts at 365 to 375 degrees F. Raised yeast doughnuts at 360 to 365 degrees F. Mini-doughnuts and donut holes at 370 to 375 degrees F. Funnel cakes at 350 to 370 degrees F. The snap-action thermostat holds the setpoint within a few degrees during normal service.
How long do doughnuts take to fry?
Cake doughnuts cook 60 to 75 seconds per side. Raised yeast doughnuts cook 50 to 60 seconds per side. Crullers cook 45 to 60 seconds per side. Mini-doughnuts cook 30 to 60 seconds total and are turned with a screen rather than flipped individually.
Can I fry chicken or french fries in the 2923SF?
The flat-bottom shallow tank is not the right geometry for chicken or french fries. Those products need a deep tank with a wire basket. The 2923SF is purpose-built for doughnut and funnel cake frying. Operators who need both should pair this unit with a standard deep fryer on the same line.
Does the 2923SF come with baskets?
No, the 2923SF ships without baskets because doughnut frying is done with a wooden dowel and a hand screen rather than a fixed basket. Single large screens, stainless steel tank covers, gas hoses, and equipment stands are available as separate accessories.
Is the unit natural gas or propane?
The 2923SF ships factory-set for natural gas at 4 inches water column manifold pressure and is easily convertible to propane at 10 inches water column. Propane conversion is a standard burner orifice swap and regulator adjustment performed by a certified gas technician.
How much oil does the tank hold?
2.5 to 3 gallons of frying shortening or oil, which is 20 to 24 pounds. Fill to the marked oil level line and top off during service as the product absorbs oil.
Can I run solid shortening in the 2923SF?
Yes. Solid all-purpose vegetable shortening is the traditional doughnut shop standard and produces the classic crisp exterior with a tender crumb. Melt the shortening at low temperature setting before ramping the burner up to frying temperature. Cold shortening on a hot burner can scorch on the tank bottom.
How often should I filter the oil?
Filter at the end of every service day through a coffee filter, doughnut oil filter cone, or portable filter unit. Skim the surface every 30 to 60 minutes during service to remove floating crumbs and any sugar that has drifted in from the draining or glazing station.
How often should I replace the oil?
Most doughnut shops replace oil every 7 to 14 days depending on volume. Replace when free fatty acid level exceeds 2.0 percent, when smoke point drops below 350 degrees F, or when oil color turns dark amber and the doughnuts start to taste like the oil rather than the dough.
What is the installation clearance?
2 inches on the sides and 6 inches at the rear for non-combustible surfaces. 6 inches on the sides and 6 inches at the rear for combustible surfaces. Always verify with local code before final installation.
Does it need a hood?
Yes. The 2923SF is a commercial gas fryer that produces grease-laden vapor and combustion byproducts and must be installed under a Type 1 commercial hood with UL 300 wet-chemical fire suppression in any indoor commercial kitchen.
Is the 2923SF NSF and UL listed?
Yes. NSF listed for commercial foodservice and UL listed for commercial gas equipment.
What does the SF in 2923SF mean?
SF designates the standard countertop flat-bottom configuration in the Comstock-Castle doughnut fryer series. The 2923 prefix is the model number. Larger units in the same series are the 2932SF (32 inch width, 75,000 BTU) and the 2941SF (41 inch width, 100,000 BTU). Floor model variants on tubular stainless legs with a stainless under shelf are also available and bring the tank surface to 36 inches.
Can I use this on a buffet or in a front-of-house display?
The 2923SF is a commercial cooking appliance not a display warmer. It is suitable for back-of-house production or behind-counter open-kitchen production where the operator is actively frying and a Type 1 hood is present. It is not a tabletop warmer.
What is the warranty?
Standard Comstock-Castle commercial warranty applies. Contact us with the order confirmation number for warranty documentation specific to your unit.
Pricing and ordering?
Doughnut fryer specification often requires a short conversation about kitchen layout, gas type, hood configuration, and any accessories needed for the workflow. Contact us for a price quote and to confirm lead time and shipping options for the 2923SF.