Beerstone: How to remove and prevent it from occuring

Every brewer, whether amateur or professional, is well-acquainted with the challenges that come with maintaining brewing equipment. One such challenge is the pesky formation of beerstone. This stubborn substance can compromise the quality of the brew and pose sanitation issues. Let's delve deep into understanding beerstone and provide effective methods to eliminate it from brewing equipment.

What is Beerstone? A Deeper Dive into the Science

Beerstone, scientifically known as calcium oxalate, is a milky-white or sometimes brownish deposit that forms on brewing equipment over time. It's a combination of minerals, primarily calcium and magnesium salts, and organic compounds left over from the brewing process. If left untreated, beerstone can harbor microorganisms, jeopardizing the quality and safety of the brew.

The formation of beerstone is a classic example of precipitation chemistry. Oxalic acid, naturally present in malt, reacts with calcium ions found in the brewing water and the malt itself. This reaction forms calcium oxalate, a salt with very low solubility in water, especially under certain conditions. The chemical equation for this reaction is: $Ca^{2+}(aq) + C_{2}O_{4}^{2-}(aq) \rightarrow CaC_{2}O_{4}(s)$. The presence of proteins and other organic molecules in the wort acts as a "binder," helping the calcium oxalate crystals adhere to surfaces and creating a tenacious, difficult-to-remove scale.

Several factors can influence the rate of beerstone formation:

• Water Chemistry: Hard water, with its higher concentration of calcium and magnesium ions, is more prone to beerstone formation.
• Mash pH: The pH of the mash and wort can affect the solubility of calcium oxalate.
• Temperature: Temperature fluctuations during the brewing process, especially the rapid cooling of the wort, can cause calcium oxalate to precipitate out of solution.

Why is Beerstone a Concern for Brewers?

Beerstone is more than just an aesthetic issue; it's a serious concern for any brewer who values quality, consistency, and safety. Here's a more in-depth look at the problems it can cause:

• Sanitation Issues: The rough, porous surface of beerstone provides an ideal breeding ground for bacteria and wild yeast. These unwanted microorganisms can hide in the microscopic nooks and crannies of the beerstone, protected from routine cleaning and sanitizing procedures. This can lead to cross-contamination between batches, resulting in off-flavors, spoilage, and even potential health risks.
• Equipment Integrity: Over time, beerstone can cause significant damage to your brewing equipment. The buildup of this scale can lead to pitting and corrosion of stainless steel surfaces, reducing the lifespan of your expensive tanks, kettles, and other equipment.
• Inconsistent Brews: The presence of beerstone can interfere with the brewing process in several ways. It can act as a nucleation site, causing excessive foaming and gushing in the finished beer. It can also alter the flavor profile of your beer, leading to inconsistent batches and a product that doesn't meet your standards.

Effective Methods to Remove Beerstone: A Brewer's Guide

While beerstone can be a stubborn foe, it's not invincible. With the right knowledge and a consistent cleaning regimen, you can keep your equipment pristine and your beer delicious. Here's a step-by-step guide to effective beerstone removal:

1. Routine Cleaning: The First Line of Defense

The best way to deal with beerstone is to prevent it from building up in the first place. A thorough cleaning after every brew is essential. Use a high-quality, brewery-approved alkaline cleaner to remove organic soils like proteins and hop resins. Scrub all surfaces with a non-abrasive pad, paying close attention to hard-to-reach areas. This will remove the "binder" that helps beerstone adhere to surfaces.

2. The Power of Acids: Dissolving the Mineral Scale

For existing beerstone buildup, an acidic cleaner is your best weapon. Phosphoric acid and nitric acid are both highly effective at dissolving the calcium oxalate that makes up the bulk of beerstone. These acids work by breaking down the mineral scale and allowing it to be easily rinsed away. When using acidic cleaners, always follow the manufacturer's instructions for dilution and contact time. Be sure to wear appropriate personal protective equipment (PPE), including gloves and eye protection, as these acids can be corrosive.

3. Specialized Beerstone Removers: A Targeted Approach

For tough, built-up beerstone, a specialized beerstone remover may be necessary. These products are formulated with a blend of acids, surfactants, and chelating agents that work together to break down and remove even the most stubborn deposits. They are often designed for specific applications, such as cleaning-in-place (CIP) systems, and can be a valuable tool in any brewer's arsenal.

4. Prevention is Key: Keeping Beerstone at Bay

Once your equipment is free of beerstone, you'll want to keep it that way. Here are some preventative measures you can take:

• Water Treatment: If you have hard water, consider using a water softener or reverse osmosis (RO) system to reduce the mineral content of your brewing water.
• Regular Acid Washing: Incorporate a regular acid wash into your cleaning regimen. This will help to prevent the buildup of beerstone and keep your equipment in top condition.
• Passivation: After cleaning with an acidic cleaner, it's a good idea to passivate your stainless steel equipment. This process creates a protective layer on the surface of the steel that helps to prevent corrosion and beerstone formation.

Safety First: A Brewer's Responsibility

When using chemical agents to clean brewing equipment, it's paramount to prioritize safety. Always:

• Wear protective gloves and eyewear.
• Ensure adequate ventilation in the cleaning area.
• Thoroughly rinse equipment after cleaning to remove any residual chemicals.
• Store cleaning agents out of reach of children and pets.

Conclusion: A Clean Brewery is a Successful Brewery

Beerstone is an inevitable challenge faced by brewers. However, with consistent cleaning, preventive measures, and the right cleaning agents, it's a challenge that can be efficiently tackled. By keeping brewing equipment free of beerstone, brewers can ensure the production of high-quality, consistent, and safe brews. Remember, a clean brewery is a successful brewery. Happy brewing!

Alkaline Brewery Wash vs. Powdered Brewery Wash - wish is the better buy?

When it comes to the critical practice of brewing hygiene, the selection of a cleaning agent is as fundamental as the malt bill or fermentation schedule. Brewers often weigh the merits of Alkaline Brewery Wash (ABW) and Powdered Brewery Wash (PBW), each offering a distinct approach to maintaining sanitary conditions vital for consistent and high-quality beer production. 

The presence of unwanted microorganisms or residual brewing byproducts can lead to off-flavors, inconsistent fermentation, and ultimately, spoiled batches. Therefore, a thorough understanding of how these cleaners work at a scientific level is paramount.

This article will delve into the scientific principles behind the cleaning action of ABW and PBW, providing a comprehensive analysis to guide brewers in making an informed decision tailored to their specific brewing environment and needs.

Chemical Composition and Cleaning Efficacy: A Scientific Perspective

Alkaline Brewery Wash (ABW)

ABW typically employs a blend of alkaline salts, often including sodium carbonate or silicates, along with surfactants. The alkalinity, characterized by a high pH (typically above 11), saponifies fats and oils, breaking them down into more water-soluble compounds that can be easily rinsed away.

Furthermore, the alkaline environment disrupts the cellular membranes of many microorganisms, contributing to their inactivation. The surfactants present reduce the surface tension of water, allowing the cleaning solution to penetrate and lift organic residues, such as proteins and carbohydrates left behind from the mash, boil, and fermentation stages.

A significant advantage of ABW is its effectiveness across a broader temperature spectrum. The kinetic energy of molecules plays a crucial role in cleaning efficiency; higher temperatures generally accelerate chemical reactions and increase the solubility of residues. However, ABW's formulation allows it to maintain a significant degree of cleaning power even at lower temperatures. 

This is partly due to the specific types and concentrations of alkaline compounds and surfactants used, which are designed to be effective without requiring excessive thermal energy. This not only saves energy but also reduces the risk of protein denaturation and adherence to surfaces that can occur at higher temperatures, making rinsing more difficult.

Powdered Brewery Wash (PBW)

PBW distinguishes itself through a more complex formulation, typically including sodium metasilicate, a highly alkaline compound that effectively hydrolyzes organic matter. The inclusion of chelating agents, such as phosphates or EDTA (ethylenediaminetetraacetic acid), is a key feature. 

These chelators work by forming stable complexes with metal ions (e.g., calcium, magnesium, iron) present in hard water and brewing residues. By sequestering these ions, chelators prevent them from interfering with the cleaning process and from depositing as scale or beer stone (calcium oxalate) on equipment surfaces. Beer stone can harbor microorganisms and is notoriously difficult to remove. 

PBW's efficacy is significantly enhanced at higher temperatures because the increased thermal energy boosts the activity of both the alkaline components and the chelating agents, accelerating the breakdown of organic soils and the solubilization of mineral deposits. However, this temperature dependency implies a greater energy demand for optimal performance.

Cost-Effectiveness and Usage Concentrations: An Economic and Chemical Equilibrium

Cost Considerations

The initial purchase price often makes ABW appear more economical, a crucial factor for budget-conscious brewers. Beyond the upfront cost, the ability of ABW to perform effectively at lower temperatures translates to potential savings in heating energy, contributing to long-term operational efficiency and a lower overall cost of cleaning. 

This is particularly relevant in regions with high energy costs or for brewing setups where heating large volumes of cleaning solution is resource-intensive.

Usage Efficiency

PBW's concentrated formulation suggests that a smaller amount of product might be needed per unit volume of cleaning solution to achieve the desired level of cleanliness. This higher cleaning power at lower concentrations can potentially offset its higher per-unit cost over time. Brewers must carefully consider the recommended dilution ratios and the total amount of cleaner used over multiple cleaning cycles to accurately assess the long-term cost-effectiveness of each option. 

Factors such as the frequency of cleaning, the volume of cleaning solution required, and the severity of fouling will influence the overall expenditure.

Environmental Impact and Safety: Balancing Ecological Responsibility and User Well-being

Ecological Considerations

The environmental impact of brewing chemicals is an increasingly important consideration. ABW's non-caustic nature often translates to better biodegradability and reduced harm to aquatic ecosystems if discharged in wastewater (though proper disposal according to local regulations is always essential). The breakdown products of ABW components are generally less persistent and less toxic compared to some of the more aggressive chemicals found in certain formulations of PBW. 

However, it's crucial to note that the environmental impact of any cleaning agent depends on its complete formulation, concentration used, and the wastewater treatment processes in place.

User Safety

The non-caustic nature of many ABW formulations generally presents a lower risk of chemical burns and respiratory irritation for users. This can be a significant advantage in environments where safety protocols might be less stringent or where users may have less experience handling strong chemicals. 

While PBW is also safe when handled correctly, its alkaline components, particularly sodium metasilicate, can be corrosive and irritating to skin, eyes, and the respiratory tract. 

Therefore, the use of appropriate personal protective equipment (PPE), such as gloves, eye protection, and potentially respirators, is even more critical when working with PBW to mitigate these risks. Brewers must prioritize safety training and ensure adherence to safety guidelines for whichever cleaner they choose.

Versatility and Material Compatibility: Ensuring Broad Application and Equipment Longevity

Versatility in the Brewery

The versatility of both ABW and PBW stems from their ability to address a wide range of organic and inorganic soils encountered throughout the brewing process. This includes removing krausen rings from fermenters (composed of proteins, hop resins, and yeast), wort residues from brew kettles (sugars and caramelized solids), and beer stone buildup in serving tanks and lines (mineral deposits). 

The ability to use a single cleaner for multiple applications simplifies inventory management and cleaning protocols, contributing to operational efficiency.

Compatibility with Materials

The long-term integrity of brewing equipment is paramount, making material compatibility a non-negotiable factor in cleaner selection. While stainless steel, the primary material in most brewing systems due to its inertness and cleanability, is generally compatible with both ABW and PBW, other materials require careful consideration. 

For instance, prolonged exposure to highly alkaline solutions like some PBW formulations can degrade certain types of rubber gaskets and seals, leading to leaks and potential contamination. Similarly, softer metals like aluminum or copper can be corroded by strong alkaline cleaners. Brewers must consult the manufacturer's recommendations for both their cleaning agents and their brewing equipment to ensure compatibility and prevent damage that could compromise the quality of their beer or necessitate costly repairs.

The decision between Alkaline Brewery Wash and Powdered Brewery Wash hinges on a nuanced evaluation of their chemical properties, cleaning mechanisms, cost implications, environmental footprints, safety profiles, and material compatibilities within the specific context of a brewery's operations. 

There is no universally "best" cleaner; rather, the optimal choice is the one that most effectively addresses the unique challenges and priorities of the brewing environment. Factors such as the scale of operation, the types of beers brewed (which can influence the nature and tenacity of residues), water hardness, energy costs, waste disposal regulations, and the brewery's commitment to safety and sustainability all play a crucial role in this decision-making process.

Ultimately, the thorough comparison of ABW and PBW highlights the scientific and practical considerations involved in maintaining impeccable brewing hygiene. 

By understanding the underlying chemistry of these cleaners and their interactions with brewing soils and equipment, brewers can make informed choices that not only ensure the production of consistently excellent beer but also align with their operational efficiency, safety standards, and environmental stewardship goals. Whether a brewery opts for the gentler, potentially more cost-effective ABW or the powerful, chelation-enhanced PBW, the unwavering commitment to cleanliness remains the cornerstone of successful brewing.

Handy Guide to PBW (Powdered Brewery Wash) for Cleaning Homebrew Beer Gear

For anyone deeply invested in the world of homebrewing, the quest for immaculate equipment is never-ending. We've all been there: staring at the bottom of a kettle with that stubborn, baked-on ring of protein, or trying to scrub the tenacious krausen residue from a fermenter. 

It's in these moments that we realize a fundamental truth: we are cleaners first, and brewers second...

Enter PBW, or Powdered Brewery Wash, a cleaning product by Five Star that has rapidly become the gold standard for both commercial and home brewers alike. 

Born from the need for a safer, effective alternative to caustic chemicals in professional breweries, PBW has established itself as an indispensable tool in every serious brewer's arsenal.

This guide will dive deep into what makes PBW so effective. We'll explore the science behind its powerful cleaning action, detail its most effective uses in the brewery, and clarify the critical distinction between cleaning and sanitizing to ensure your beer is not only delicious but safe from spoilage.

PBW at a Glance: Pros & Cons

Pros (What We Love)

• ✓ Unmatched Cleaning Power: Effortlessly dissolves the toughest baked-on organic soils like krausen and kettle trub.
• ✓ Safe on All Equipment: Non-corrosive formula is safe for stainless steel, plastic, glass, and soft metals.
• ✓ Reduces Manual Labor: The "soak and forget" method eliminates the need for hard scrubbing, saving time and effort.
• ✓ Effective in Hard Water: Contains chelating agents that prevent mineral deposits like beer stone from forming.

Cons (What to Consider)

• ✗ Higher Cost: Generally more expensive per use than DIY alternatives like OxiClean or sodium percarbonate.
• ✗ Requires Hot Water: Works most effectively at high temperatures (140°F+), which requires an energy input.
• ✗ Cleaner ONLY, Not a Sanitizer: You must still sanitize equipment on the cold side of your brewing process after cleaning.
• ✗ Thorough Rinse Needed: A complete and thorough rinse with hot water is required to remove all residue before use.

The Science of Clean: How PBW Annihilates Grime

PBW's effectiveness isn't magic; it's a masterful blend of chemistry designed specifically to tackle organic brewing soils. Its power comes from a multi-pronged attack:

The Alkaline Powerhouse: Sodium Metasilicate

At its core, PBW is an alkaline (caustic) cleaner. Sodium Metasilicate provides the high pH needed to break down the two toughest culprits in the brewery: proteins and fats. 

It works through a process called saponification, turning baked-on grime into water-soluble, soap-like substances that simply rinse away.

The Oxidizing Power: Sodium Percarbonate

This is the "active oxygen" component. When dissolved in hot water, Sodium Percarbonate breaks down into hydrogen peroxide and sodium carbonate. The hydrogen peroxide is a powerful oxidizing agent, literally lifting organic soils like yeast and hop residue off surfaces. 

The sodium carbonate softens the water, allowing the cleaners to work more effectively.

The Unseen Hero: Chelating Agents

This is PBW's secret weapon. Hard water contains minerals like calcium and magnesium, which can bind with soils to form tough deposits like beer stone. 

Chelating agents in PBW grab onto these minerals, taking them out of the equation. 

This prevents beer stone from forming and allows the primary cleaning agents to attack the organic grime without interference.

Brewer's Insight: Why OxiClean Isn't a True PBW Substitute

Many brewers attempt a DIY PBW using OxiClean (mostly sodium percarbonate) and a TSP substitute. While this provides some cleaning power, it lacks the crucial chelating agents. 

In areas with hard water, this DIY mix is far less effective at preventing beer stone and fully removing grime compared to the professionally formulated PBW.

A Brewer's Practical Guide to Using PBW

Knowing how PBW works is one thing; using it effectively is another. Here's how to get the most out of this powerful cleaner.

The PBW User Manual: Dosage, Temp, and Time

Using PBW is straightforward, but following these parameters is key to success:

• Dosage: For general cleaning, use 1 ounce of PBW per gallon of water. For heavy-duty tasks like caked-on kettle trub or long-neglected fermenters, increase this to 2 ounces per gallon.
• Temperature: PBW works best in hot water. The ideal temperature range is 140-160°F (60-71°C). This temperature is crucial for fully activating the sodium percarbonate.
• Contact Time: For most applications, a 30-minute soak is sufficient. For truly stubborn messes, an overnight soak works wonders. The beauty of PBW is that it does the work for you—no scrubbing required.
• Rinsing: After soaking, you must rinse all equipment thoroughly with hot water to remove any chemical residue.

Key Applications in the Brewhouse

• Kettles and Fermenters: An overnight soak with PBW will dissolve the toughest krausen rings and burnt-on trub, leaving your stainless steel or plastic looking brand new.
• Kegs and Draft Lines: Regularly cleaning your kegs and beer lines with a PBW solution is critical for preventing off-flavors and infections. Circulate the solution through your lines for 15-20 minutes.
• Bottles and Label Removal: Struggling with sticky beer bottle labels? A 30-minute soak in a hot PBW solution will cause most paper labels to slide right off, and the solution will dissolve any sediment inside.
• Small Parts: Don't forget to soak your smaller items! Ball lock connectors, clamps, gaskets, and racking canes can all be cleaned together in a bucket of PBW solution.

The Golden Rule: Cleaning is NOT Sanitizing

This is the most critical concept for any brewer to master, and it is non-negotiable. While PBW is an exceptional cleaner, it is NOT a sanitizer.

Understanding the Difference

• CLEANING: The process of removing all visible dirt, grime, and organic soil. This is what PBW does. You must clean a surface before you can effectively sanitize it.
• SANITIZING: The process of reducing invisible microorganisms (bacteria, wild yeast) to a safe level where they cannot spoil your beer. This is what products like Star San do.

Even after a thorough PBW cleaning, a surface that looks perfectly clean can still be covered in microscopic beer spoilers. Any piece of equipment that touches your beer after the boil (the "cold side") must be sanitized immediately before use. This includes fermenters, airlocks, siphons, kegs, bottles, and bottling wands. 

Skipping the sanitizing step is a gamble that will eventually lead to an infected, undrinkable batch of beer.

PW has rightfully earned its place in breweries around the world. Its powerful, scientifically formulated cleaning action saves brewers time, effort, and the frustration of scrubbing. By dissolving tough organic soils and preventing mineral buildup, it provides the perfect clean slate required for brewing high-quality, consistent beer.

By integrating PBW into your cleaning routine and always following up with a no-rinse sanitizer on your cold-side equipment, you elevate your process and significantly improve your chances of brewing the perfect pint, every time.

What is the best homebrew sanitizer?

Embarking on a homebrewing journey and in search of the finest sanitizers to ensure the best brew? 

You're in the right place.

We know a thing or three about sanitizer.

The essence of a flavorful beer lies not just in the ingredients but also in the cleanliness and sanitation of your equipment. Any seasoned homebrewer will emphasize the importance of immaculate equipment and bottles to ward off any undesirable bacteria that might ruin your concoction.

Recall a time when your brew was compromised due to insufficient cleaning? You beer was wrecked as it was infected?

It's an agonizing experience, isn't it?

You spend the time and money on malt, yeast and hops and then it's simply undrinkable acid. 

Want no fuss, just need the good stuff? The good oil on sanitizer? Regardez-vous:

Sanitizer	Pros	Cons
Star San	Highly Effective: Rapidly kills microbes and does not require rinsing, leaving behind a foam that can benefit yeast health. Non-Toxic: Made from food-grade phosphoric acid which is safe for use. Ease of Use: Only requires contact for 30 seconds to be effective.	Foam Production: Produces substantial foam which can be mistaken for residue or contamination by new brewers. Sensitive to Environment: Less effective in hard water or when improperly diluted.
Iodophor	No-Rinse: At proper dilutions, it does not require rinsing and leaves minimal residual taste or odor. Indicator: Changes color to indicate effectiveness and proper dilution. Broad Spectrum: Effective against a wide range of organisms.	Staining: Can stain plastics and fabrics with prolonged contact. Short Shelf Life: Once diluted, it loses potency within 24-48 hours. Sensitive to Light: Degraded by light exposure, requiring storage in dark containers.
One Step	No Rinse Required: Easy to use without the need for rinsing, making it quick and convenient. Environmentally Friendly: Oxygen-based and biodegradable. Safe: Non-toxic formula makes it a safer choice for home brewers.	Less Effective on Hard Surfaces: May not be as effective as other sanitizers on hard, non-porous surfaces. Requires Longer Contact Time: Generally needs at least 2 minutes to sanitize effectively.
Bleach	Highly Affordable: Widely available and cost-effective. Powerful Disinfectant: Extremely effective at killing a wide range of microbes. Versatility: Can be used for various cleaning tasks beyond brewing.	Corrosive: Can damage stainless steel and other surfaces if not thoroughly rinsed. Residual Smell: Leaves a strong chlorine odor that must be completely rinsed to avoid flavor impact. Rinsing Required: Must be thoroughly rinsed to prevent contamination.
Powder Brewery Wash	Effective Cleaner: Excellently removes organic residues like proteins and lipids. Versatile: Safe on all materials including stainless steel and plastic. Environmentally Friendly: Biodegradable and non-hazardous under typical use conditions.	Requires Thorough Rinsing: Must be completely rinsed off to prevent interaction with sanitizers. Not a Sanitizer: Only cleans, does not sanitize—sanitization step is still necessary. Optimal Performance Requires Hot Water: More effective with warm to hot water, increasing energy usage.

Let's dive in and explore the top sanitizers that will shield your beer, cider, or wine from any brewing adversaries.

1. Star San: The Pinnacle of Sanitizers

Star San is renowned for its formidable ability to annihilate any microorganisms threatening your brew. Characterized by its makers as "a self-foaming acid sanitizer apt for brewing, dairy, and other edibles," it stands out as a potent bactericide and fungicide. 

What's more, it's resilient against excessive organic soils and diminishes water spotting. Comprising phosphoric acid and dodecylbenzenesulfonic acid, Star San is a no-rinse solution — a significant advantage for brewers eager to get brewing.

Usage: Star San can be applied through spraying or soaking equipment and bottles. A ratio of one ounce to 5 gallons of water ensures optimal protection against bacteria.

However, its superiority comes with a premium price tag.

2. Iodophor: The Trusted Choice

Iodophor, favored by the beer brewing community, has roots in the food service and medical sectors for equipment sanitation. A trifecta of detergent, germicide, and sanitizer, Iodophor promises sanitation in approximately 10 minutes. As with Star San, it requires no rinsing at the suggested concentration.

A word of caution: Iodophor can stain clothing, so exercise care during use.

3. Powdered Brewery Wash (PBW)

Originally embraced by commercial breweries, PBW has won the hearts of homebrewers for its sanitizing prowess. Many veteran brewers laud its effectiveness. PBW not only sanitizes but also aids in removing beer labels from bottles.

A tip: You can craft your own PBW alternative using household products. Blend a home brand like Tide or Oxiclean with a metasilicate-rich cleaner like Red Devil TSP/90 in a 70/30 mix to craft a DIY sanitizer.

4. Laundry Soakers: The Unexpected Savior

Surprisingly, common laundry soakers can serve as sanitizers. Products boasting 'oxy' labels typically contain sodium percarbonate, a chief ingredient in many renowned soakers. We can personally testify that this is the key product we use to prepare our beer bottles and brewing drum - it's cheap an effective. 

5. Bleach: The Old Reliable

Bleach, while commonplace, can be a potent sanitizer for homebrewing. A solution of 1 tablespoon of bleach to 1 gallon of water, followed by a 20-minute soak, should suffice. However, due to its strong odor, rinsing is advised. For quick results, opting for faster-acting solutions like Star San might be more prudent.

The Verdict on the best beer making sanitizers

When it comes to selecting the ideal homebrewing sanitizer, consider these factors:

• Premium quality and user-friendliness come at a price, making PBW and Star San top contenders.
• For a mid-tier option, products containing sodium percarbonate are recommended.
• For those on a budget seeking extended sanitization, traditional bleach is a viable choice.

In the realm of brewing, cleanliness is paramount. So, embark on your brewing journey with the best sanitization practices in tow!