Bird seed blocks, also known as bird seed cakes or suet cakes, are an excellent source of energy and nutrition for wild birds during the winter months or year-round. But what ingredients allow these mixes of seeds, nuts, and other goodies to hold together in a solid block that can be hung up for birds to peck away at over time? Here are the key ingredients and methods that give bird seed blocks their characteristic compact shape.
Binders
The primary ingredient that enables pressed seed blocks to maintain their form is usually a binder or binding agent. This is what allows the other ingredients like seeds, nuts, fruit, and nectar to stick together when compressed rather than crumbling apart. Some common binders used in bird seed blocks include:
- Fats and oils – These can come from suet (beef or mutton fat), lard, or vegetable-based oils. Melted fat solidifies when cooled, gluing the dry ingredients together.
- Waxes – Paraffin wax derived from petroleum is commonly used. Beeswax, carnauba wax, or soy wax may also be used.
- Corn syrup or molasses – These sticky sweeteners act as excellent binders.
- Hummingbird nectar – The thick sugar solution helps bind nectar-based mixes.
- Honey – Another sticky binder that also adds nutritional value.
- Peanut butter – Adds nutrition and binding properties.
Fats and waxes like suet and paraffin wax are especially popular because they form solid blocks that retain their shape well with minimal crumbling. The percentage of fat or wax can be adjusted to create harder or softer blocks as desired.
Compaction
In addition to the binder, seed blocks must be compressed to enable the ingredients to stick together. This is done using a process called compacting or pressing:
- Dry ingredients like seeds, nuts, dried fruit, oats, etc are thoroughly mixed with the chosen binder in liquid form (melted fat, syrup, etc).
- The mixture is poured into molds, which may make individual blocks, balls, cubes, etc.
- A hydraulic press applies significant pressure to compress the mixture very tightly.
- The compacted blocks are ejected from the molds and allowed to solidify as the binder cools or dries.
The pressure ensures components are packed tightly together so they hold their shape. The hardness of the final block depends on the pressure applied, as well as the amount and type of binder.
Setting Agents
While fats, waxes, and other sticky binders allow blocks to hold together initially, setting agents help harden and fortify them for longer integrity. Some supplements added to improve firmness and longevity include:
- Flour – Wheat, oat, or corn flour helps dry out the mixture for firmer blocks. The starch absorbs excess moisture.
- Gelatin – Sprinkling in some unflavored gelatin can reinforce the block as it sets.
- Ground eggshells – These add calcium carbonate for extra stability.
- Cement, plaster, or sawdust – Small amounts of these very dry, absorbent ingredients soak up moisture for a tougher texture.
Aside from assisting with firmness, these supplements also add extra nutrition like protein, fiber, and calcium. However, they are optional and only used in small quantities to prevent changing the texture too significantly.
Preservatives
For bird food blocks designed to last a while through different weather conditions, preservatives help prevent spoilage so the blocks remain safe for extended bird feeding. Some potentially utilized preservatives include:
- Vitamin E – An antioxidant that resists rancidity of fats and oils.
- Mixed tocopherols – Concentrated antioxidants that also prevent rancidity.
- Rosemary extract – A natural extract with antioxidant properties.
- Citric acid – Helps block mold, yeast, and bacteria growth.
- Potassium sorbate – A mild food-grade preservative.
Check the ingredient list on any bird food block product for which specific preservatives, if any, are included. Most aim to use natural options like rosemary extract and vitamin E.
Ideal Ingredients
While the binding agents and manufacturing process ensure blocks hold together, the other ingredients also impact the integrity. Some of the best components for compressed bird blocks include:
- High oil seeds like black oil sunflower, nyjer, and safflower – Their natural oils help bind them together.
- Shelled nuts like peanuts, almonds, and cashews – Their oils also assist binding.
- Rolled or quick oats – Their starch absorbs moisture for a firmer texture.
- Dried fruits like raisins, cranberries, cherries or blueberries – They add nutrition and tend to maintain shape well.
- Crumbled suet or lard – Increases the fat content for excellent binding effects.
- Cornmeal – Provides an absorbent, granular texture.
- Cracked corn – Similar to cornmeal in effects.
Ingredients should be chosen not just for nutrition, but also for how they contribute to a compact, cohesive blend. Some nutritionist developed blocks may even mix in supplements like calcium grit, bird vitamins, dried mealworms, or spirulina for added benefits.
The Manufacturing Process
Producing commercial bird food blocks on a large scale involves a standardized industrial process. Here are the typical steps involved:
- Measure out precise amounts of dry ingredients like seeds, nuts, grains, dry fruit, etc. according to recipes.
- Mix dry blend thoroughly to distribute components evenly.
- Melt any solid fats like suet or lard in large heated vessels, bringing to around 140-150°F to liquefy.
- Mix in any liquid ingredients like corn syrup, molasses, or oils.
- Combine the wet binder mixture with the dry ingredient blend in a large mixer.
- Allow to mix until evenly incorporated into thick paste.
- Pour batches into molds on press machine.
- Compress with high pressure plates at up to 40,000psi.
- Eject hardened blocks from molds.
- Package blocks individually or in bulk as product cools and sets fully.
Automated machinery allows for high volume production. Blocks may be made in wide varieties catering to different birds with mixes like chicken layer crumble blocks, fruit and nut blocks, nectar blocks, etc.
Benefits of Bird Seed Blocks
These compressed cakes offer a number of advantages for birds and bird lovers:
- Convenient, mess-free feeding – No scattering of loose seed.
- Easier for some birds to eat than loose feed.
- Allows feeding of suet and nuts without messy meshes.
- Prevents selective eating by including a seeded blend.
- Higher calorie than loose seeds for more energy.
- Some add supplements for enhanced nutrition.
- Can customize recipes for different bird species.
- No need to frequently refill feeders.
- Can hang blocks in multiple places.
The compressed blocks last longer thanks to their sturdy nature, while offering birds a complete balanced meal. Different binders, textures, shapes, and supplements allow endless possibilities too. No wonder birding enthusiasts love these mess-free, nutritious wildlife feeders!
FAQs
What is the best binder for bird seed blocks?
For durability and wildlife safety, rendered suet (beef fat) is one of the best binders. The fat helps bird blocks retain their shape and hardness in any weather. Paraffin wax, beeswax, and peanut butter also make excellent stable, non-toxic binders.
Do you need to refrigerate bird seed blocks?
Most bird seed blocks containing animal fat or suet will need refrigeration to prevent spoilage at warm temperatures. However, versions containing plant-based fats like soy oil or coconut oil can be left unrefrigerated. Check package instructions for storage guidance.
How long do bird seed blocks last?
With the right preservation and storage, commercially made seed blocks typically last 1-2 months. Homemade versions may start drying out after 1-2 weeks. Consumption time depends on how many birds visit – a block can last a few days to a few weeks.
What birds eat seed blocks?
Many birds relish fat-rich suet blocks, including woodpeckers, nuthatches, chickadees, titmice, wrens, bluebirds, mockingbirds, thrashers, and starlings. Seed blends attract finches, sparrows, juncos, doves, cardinals, and more. Nectar blocks appeal to orioles and hummingbirds.
Should seed blocks be placed in sun or shade?
Shaded areas are preferable to prevent spoilage, moisture damage, and any melting in summer heat. A covered porch or eave placement is ideal. If in direct sun, choose a spot that gets sunlight only part of the day.
Conclusion
Bird seed blocks manage to defy gravity by compacting nutritious mixes into a cohesive cake. The secret lies in sticky binders like melted fats and oils that glue ingredients together when cooled. Compression and optional setting agents further fortify the blocks to maintain their solid block shape for easy bird feeding. Understanding the ingredients and manufacturing processes that produce hardy, nutritious suet and seed blocks can help consumers choose the best options for attracting backyard birds.