Why Steam?
What’s the Big Deal?
Cooking Energy Sources
• Radiation – visible light, infra-red, microwaves
• Convection – heated air, steam
• Conduction – contact with a heated surface or
liquid
Steam Cooking
• Braising Pans (as a steamer) – boiling water provides
atmospheric pressure steam (0 PSI) 212° F. Air acts as an
insulator and slows cooking, compared to a “true” steamer.
• Kettles – jacket wall heats to the steam temperature, pressure
inside jacket gives a temperature above 212° F for cooking.
• Steamers/Combis – steam at atmospheric pressure (0 PSI) 212°
F condenses on food surface and transfers latent heat directly.
Heat versus Temperature
• Heat is energy – the energy of molecular
motion in a material
• Temperature is a measure – the measure of
kinetic energy of the molecules in a material
Boiling v. Pressure
• The temperature where water changes to steam
varies depending upon the pressure
• At sea level (~14psi), water boils at 212°F
• At 6000’ water boils at 201°F
• At 50psi water boils at 298°F
Temperature is related to Heat…
• One BTU is the heat
required to raise the
temperature of one
pound of water by 1°F
…but not always
• Sometimes heat changes the structure
(phase) of a material instead of raising the
temperature
– Ice to Water
– Water to Steam
Why Steam?
• Definition:
Steam – invisible gas into which water is changed by boiling [Oxford
American Dictionary]
• Advantages:
–
–
–
–
Flows easily through pipes and tubing
Carries more energy than air or radiation
“Wants” to become water
Has no odor or taste
• Disadvantages:
– “Wet” environment – does not “brown”
– Pressure and burn hazards
– Lime scale
Enthalpy of Steam
•
BTU (British Thermal Unit) = the amount of heat required to raise the
temperature of one pound of liquid water by 1 degree Fahrenheit at its
maximum density, which occurs at a temperature of 39.1 degrees
Fahrenheit. One BTU is equal to approximately 251.9 calories or 3.7
Watts.
•
Enthalpy = heat content capable of doing work
•
Sensible heat = portion of heat content introduced into water raising it
from 32 to 212 degrees Fahrenheit (at 212° = 180 BTUs)
•
Latent heat = amount of heat energy introduced into 212 degree water to
convert it into 212 degree steam (= 970 BTUs at atmospheric pressure)
Sensible and Latent Heat
• Sensible heat is the heat that changes the
temperature of a material – it can be sensed
• Latent heat is the heat associated with a phase
change of a material – it is “within” the material but
not sensed by a temperature change
Latent Heat does the Cooking
STEAM
WATER
Pressure and Temperature
• As pressure increases, so does the sensible heat
and temperature of steam
• Latent heat decreases slightly
PRESSURE
TEMPERATURE
SENSIBLE HEAT
LATENT HEAT
0 PSI
212° F
180 BTU
970 BTU
5 PSI
227° F
195 BTU
961 BTU
15 PSI
250° F
218 BTU
946 BTU
50 PSI
298° F
267 BTU
912 BTU
100 PSI
338° F
309 BTU
881 BTU
Heat Transfer
• The heat transfer rate of condensing steam is
much greater than the heat transfer of air
convection
• Example: you can put your hand into a 212°F (or
higher) oven momentarily and not get burned
• DO NOT put your hand into steam at 212°F. You
WILL get burned.
Steam Cooking
• Steam is created when water absorbs heat (latent
heat of 970 BTU/lb) and changes to steam…but the
temperature stays at 212°F
• Food is cooked when steam condenses on the food
and releases its latent heat
• AND THAT’S A LOT OF HEAT!!
Summary
• Steam cooks because it releases a large amount
of heat to the food.
• This process occurs when the steam condenses to
water, releasing the latent heat.
• The heat transfers more rapidly than normal
convection air cooking.
• The product remains moist.
Industry
Pressures/Boilerless
Manufacturer standards increasing
New certifications available (rebates)
Energy Star, Green Rest., Even LEED
Three questions all potential customers should be asked?
What product are you planning on steaming?
vegetables, starches, proteins, re-therming or seafood?
In what manner are you planning on steaming?
batch, versatile or ala carte
What volume do you need? How many pans?
Defining Application Style/ Steamer need
Coil Pressure Steamer
Remote Boiler
Higher temp.
Quicker cook times
No manual intervention
High energy use
High water use
Loss of time on pressure down
flavor transfer
Hard on delicate vegetables
Tend to leak at door gaskets
Boiler Steamers
Most sold today are open systems allowing for ala carte style cooking.
Atmospheric steam in lieu of pressure in the cooking cavity.
Having a boiler allows unit to be used as a single source power supply for existing or new
direct steam kettles.
Provides availability to meet spec and or customer predisposition that a boiler system is
what they want.
Accessible cavity (ala carte cooking, fastest recovery time, easy on vegetables, no flavor
transfer)
High water usage, high energy use, demands high maintenance, requires harsh
chemicals, boilers are the most problematic piece of equipment In the kitchen. High cost
of ownership.
Generators vs. Boilers
What's the difference?
1970’s zero pressure and a call to eliminate the boiler requirement.
To preserve food integrity, “zero” pressure steamers have an
advantage over pressure steaming
Open system/closed system
Accessible cavity (ala carte)
Still all the issues that boiler steamers have minus the requirement of
a boiler…
Boilerless Steamers
Economic and ecological pressures
move steamers to boilerless
technology.
What is boilerless?
To preserve food integrity, “zero”
pressure steamers have an
advantage over pressure steaming
Open system/closed system
Accessible cavity (ala carte) or
Batch
Still all the issues that boiler
steamers have minus the
requirement of a boiler…
Why boilerless is better.
Less water consumption than traditional steamers. (saving money on utilities)
Less maintenance required (no traditional de-liming of generators or boilers.
(saving money on labor)
No harsh chemicals (unit cleans up with simple vinegar and water solution)
meaning less cost of cleaning agents and less impact on environment.
Very near the same cook times as a generator unit (with all the savings)
Additional benefits of Connectionless steamers
Utility Study
Studies conducted by Fisher-Nickel,
Inc. and the Foodservice Technology
Center confirm that replacing a
conventional steamer with a
connectionless steamer in a high
volume restaurant will save
$6,083.00 each year per
compartment in utility savings.
That is $12,166.00 each
year per double stack steamer!
The information in this table is based on data generated by Fisher-Nickel, Inc. and the Food Service Technology Center - MWD ICP: Evaluating
the Water Savings Potential of Commercial Connectionless Steamers - Agreement No. 55354- Final Report
“Boilerless”
Batch oriented
Holding Cabinet
Energy Star Rated
Variable capacities, 3,6
Electric
Digital timer
Water Connection optional
Water filter optional
Easy to clean (mirrored interior)
High rate of continuous steam
“Boilerless”
Connected a la carte style Boilerless base
Variable capacities, 3,5,10
Electric/Gas
90 minute digital timer (each cavity of stacked)
Single water connection
Water filter optional
Easy to clean (mirrored interior)
High rate of continuous steam
Steam Generator
Generator base
Variable capacities, 3,5,6,10
Electric/Gas
Separate 60 minute timers
Available with two water connections
Water filter recommended
Steam on demand
Versatile steamer able to dispose of the waste from shell fish
Boiler Based
Boiler (in cabinet base)
Installation required
Needs deliming and daily blow-down
Heavy water usage
Rapid recovery and high steam production
A la carte/heavy duty production steaming
Can power adjacent kettle
Competitive features
First of All, What is a
Steam-Jacketed Kettle?
It’s a Pressure
Vessel Designed
to Transfer Heat
or Energy From
Itself to the
Product Inside it.
How it Works…
Hemispheres,
ASME, Energy,
Pressure,
Conduction.
Steam Jacketed Kettle
Replaced the Stock Pot on the Open Range
Why Use a Kettle?
Labor Savings
Product Quality
Safety
Energy Efficient
Ease of Cleaning
Low Interaction
with Acid Foods
Ergonomics
Space
Limitations
Kettle Categories
• Direct Steam Kettles (Require a Boiler)
• Self-Contained Kettles (Gas or Electric)
Sub Categories
• Table top, Stationary Floor, Tilting Floor
Direct Steam
Oldest of All
Kettle Designs
Requires
External Steam
Source (Boiler)
Broad range of
Sizes
Least
Temperature
Control
Self-Contained
Gas Kettles
Heat Exchange
System Between
the Kettle Jacket
and Gas Burner
Thermostatic
Control of Gas
Burner
Natural Gas and
Liquid Propane
Altitude Sensitive
Medium Efficiency
Stationary and
Tilting
Self-Contained
Electric Kettles
Elements
Located Within
the Jacket
Thermostatic
Control of
Elements
Voltage
Dependent
High Efficiency
Stationary and
Tilting
Table Top Kettles
Stationary vs. Tilting
STATIONARY
• Unlimited Size
• Smaller Footprint
• Insulated
• Draw-Off Provided
• Harder to Clean
TILTING
• 80-Gallon and Below
• Larger Footprint
• Non-Insulated
• Draw-Off is Optional
• Easier to Clean
Cooking Energy Source
Kettles Cook Via Contact with a Heated Surface
Heat-Up and Cooking Speed are Determined by:
•
•
•
•
Jacket Coverage – 1/2, 2/3, Full
Steam Pressure Determines Temperature
Movement of the Product Inside Kettle
Heat Loss on the Walls and Upper Surface
Pressure and Temperature
PRESSURE
TEMPERATURE
SENSIBLE HEAT
LATENT HEAT
0 PSI
212° F
180 BTU
970 BTU
5 PSI
228° F
196 BTU
960 BTU
10 PSI
240° F
208 BTU
950 BTU
15 PSI
250° F
219 BTU
945 BTU
35 PSI
281° F
250 BTU
924 BTU
50 PSI
298° F
267 BTU
912 BTU
100 PSI
338° F
309 BTU
880 BTU
Speed & Volume Production
Heats 1/3
Faster than
Stock Pots
Larger Single
Batches
Easier Product
Transfer
Safety
Permanent
Attachment
to Stand or
Base
SelfContained
Heat Source
Protection –
Pressure,
Temperature,
Power
Precise
Control Over
Draw-Off and
Pouring
Energy Efficiency
Greater
Heated
Surface
Area
SteamJacket Heat
Source –
Electric, Gas
or Direct
Precision
Heat
Control
Ease of Cleaning
Even Spread of Heat – No
Burnt on Food
Drain or Tilt Mechanism
for Access
Low Acid Interaction
Stainless Steel
Construction
Type 316 with
Molybdenum
Added for
High
Resistance to
Acid Foods
Ergonomics
No Heavy Lifting
Single Person Operation
Low Impact Tilt and Crank Mechanisms
Positive Stop On Crank Systems
Controls in a Viewable Location
Space Limitations
Footprint is Less as Volume
Increases – Compared to
Multiple Stockpots
Free up Range top Space for
Pan Frying and Other
Techniques
Free up Sink Space for
Smaller Pots and Pans
Kettle Sizing Chart
Working vs.
Nominal
Capacity
Allow for
Growth
Multiple Kettle
Flexibility
Competitive Feature Sheets
The Braising Pan
Modern Braising Pan
Braising Pan Versatility
Griddle Pancakes,
Sausage and Eggs
Cook Soup and
Grill Hamburgers
Boil Pasta &
Sauce and Steam
Vegetables
Stir-Fry an Entrée
or Slow-Cook a
Roast
Make Pudding
Braising Pan Sizing
• Working vs. Nominal Capacity – surface
area or pan volume
• Allow for Growth
• Multiple Pans add Flexibility
Floor Model
Braising Pans
30 & 40-Gallon
Capacity
Electric, Natural
Gas and Propane
Electronic Ignition
or Standing Pilot
(Gas, Manual-Tilt
Only)
Center Tilt
Open Frame –
Tubular Leg
Available on
CASTERS
TD/FPC Table Top
Braising Pan
Manual-Tilt
10-Gallon
Electric Only
Optional
Stand and
Drain Cart
Lid Features
Safety First
Inside Brodgett Gas
Braising Pans
Control Box
Thermostatically
controlled
Tilting Cut-Off
Switch
24 turn worm
gear
Power tilt
available
Water resistant
controls
Faucet bracket
standard
Tilting control “Worm Gear”
Gas units – Uses fins to distribute energy
Short and Long Fins that Capture
Burner Assembly
Uneven cooking in competitive models
Electric elements attach directly to the bottom of the pan
Electric Elements
Braising Pans
Cooking Surface
Sanded
Finish
Holds
the oil
3” Radius
Corner
Prevent
corner
scorching
Coved
Sides
Use
rounded
utensils
Gallon
Etch-Marks
Volume
control
5/8 inch
clad plate
Even Heat
Cooking Surface
Which Braising Pan Would You Rather Spend The Next 20 Years Cleaning???
Why open legs?
Why open leg stands vs cabinet style
1) No Pinch Points for accidents to happen.
2) No hiding places for vermin or
infestations.
3) Far easier to clean (saving Time)
Accessories
Competitive features sheet
Download

tilting - Blodgett Oven