Mastering the Bypass: Perfecting Coffee Strength and Flavour Balance

When it comes to appreciating the nuances of specialty coffee – precision is everything. From grind size to the brewing ratio, each variable plays a crucial role in determining the final flavour of your brew. Among the many techniques available to refine your coffee, the bypass brew stands out as a method that allows for precise control over your coffee’s strength without compromising its aromatic and flavour qualities. This guide will help you master the bypass brew, ensuring that your coffee captures everything the beans have to offer.

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What is a Bypass Brew?

The bypass brew technique involves adding a specific amount of water to your coffee after brewing. This method is particularly beneficial when the initial extraction yields a brew that is more concentrated (or ‘stronger’) than desired, with a higher Total Dissolved Solids (TDS) percentage. By diluting the brew post-extraction, you can adjust the strength while maintaining that balanced flavour profile and still allowing the coffee’s aromatics to shine.

Why Use the Bypass Method?

Simply put, the bypass method allows coffee professionals and enthusiasts to optimise their brews by:

1. Maximising Aromatics: Specialty coffee often features complex and nuanced aromatics that can be overshadowed by a strong brew. These subtle aromas become more prominent when the strength is reduced, allowing for a more engaging sensory experience.
2. Balancing out Extraction: A concentrated brew can lead to an overpowering tactile experience, potentially masking the more delicate flavours. The bypass method helps to balance these elements, ensuring that the full spectrum of flavours is preserved and appreciated.
3. Optimising the Experience: Coffee is deeply personal, and the bypass method allows you to ensure each cup is at the optimal strength without compromising the integrity of the initial extraction. This flexibility ensures that the coffee’s unique characteristics are fully expressed.

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The Importance of Extraction Quality Over Strength

When adjusting coffee strength, it’s essential to prioritise extraction quality over merely targeting a higher TDS. A well-extracted coffee maximises the potential of the beans, resulting in a balanced flavour profile that highlights both the acidity and sweetness intrinsic to the coffee.

A focus on extraction quality ensures that even stronger brews maintain a harmonious flavour. If you achieve a high-quality extraction, the coffee’s complexity and balance will be preserved, even when adjusting the strength with the bypass method. Conversely, a weaker coffee is more challenging to correct. While lab techniques like freeze concentration can address this, they are impractical for everyday use, reinforcing the importance of achieving a optimal extraction from the start​

Measuring Extraction Yield Before Bypassing!

Before you begin adjusting your brew with the bypass method, it’s crucial to measure the extraction yield. Extraction yield is the percentage of coffee solubles that have been dissolved out of the coffee grounds during brewing. Knowing this value helps you understand how effectively you’ve extracted the coffee’s flavour compounds. The formula to calculate extraction yield is:

Extraction Yield Formula:

Extraction Yield (%)= (TDS % x Brewed Coffee ml) ÷ Coffee Dose g

Where:

• TDS (%): This is the Total Dissolved Solids percentage, which you measure using a refractometer.
• Brewed Coffee (ml): This is the final weight of the brewed coffee (the liquid that you collect in the carafe).
• Coffee Dose (g): This is the weight of the dry coffee grounds you started with.

Why Aim for Maximum Extraction Yield?

Maximising extraction yield is not about extracting everything possible from the coffee grounds but rather extracting the best of what the coffee has to offer. Exceeding a certain extraction yield can lead to the release of undesirable flavours, such as bitterness and astringency. However, understanding the extraction limit of your beans allows you to push the boundaries of flavour dissolved in your cup.

Fun Fact: A more uniform grind can help you achieve extraction yields of up to 24% without introducing harsh, astringent qualities into your cup. This is because a consistent grind size ensures that water flows evenly through the coffee bed, allowing for a more uniform extraction of solubles​ from your dose.

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How to Calculate Bypass Water for Your Perfect Brew

To achieve your ideal coffee strength using the bypass method, assuming you have a coffee refractometer, you can use this formula:

Bypass Water Formula:

Bypass Water (ml) = [(Brewed Coffee ml × Actual TDS %) ÷ Target TDS %​ ] − Brewed Coffee ml

Where:

• Brewed Coffee (ml): The weight of the coffee liquid immediately after brewing.
• Actual TDS (%): The measured strength of your brewed coffee before dilution.
• Target TDS (%): The desired strength for your final cup.

Step-by-Step Guide:

1. Brew Your Coffee: Start with a well-executed extraction that captures the coffee’s full range of flavours and aromatics.
2. Measure Brewed Coffee: Weigh the coffee post-brewing, for example, 250ml.
3. Determine Actual TDS: Measure the TDS percentage using a refractometer. Suppose it’s 1.5%.
4. Set Your Target TDS: Choose your desired strength, such as 1.2% TDS.
5. Calculate Bypass Water: 
   Apply the formula:
   Bypass Water (ml) = [(250ml × 1.5%​) ÷ 1.2%] −250 ml = 62.5ml
   
6. Adjust Your Brew: Add 62.5ml of hot water, stirring to ensure even dilution.
   

Tips for a Balanced Brew:

1. Use Quality Water: Filtered water prevents any off-flavours from interfering with the delicate aromatics of your coffee.
   
2. Adjust Gradually: Add bypass water in small increments, tasting as you go to achieve the perfect balance.
   
3. Record Your Findings: Keep track of your process to replicate successful results consistently.

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Elevate Every Cup with Balance and Precision

The bypass brew method is a powerful tool to ensure you achieve optimal flavour and a relative balance of strength that is indicative of the brewing method, while also remaining subjective to your specific requirements. When you focus on extraction quality while remaining conscious of the option to make precise adjustments to strength post-brew, you can ensure that your coffee delivers the full spectrum of flavours and aromas.

Whether you’re brewing at home or serving customers, mastering the bypass method is a testament to your dedication to coffee excellence. So the next time you brew, consider the impact of the bypass method and how it can elevate your coffee experience.