W-34/70 vs. S-23: Saflager Comparisons

Choosing between Saflager W-34/70 and S-23 significantly impacts your lager’s final profile. W-34/70 offers an exceptionally clean, crisp German-style lager, ideal for showcasing malt and hop character with minimal esters. S-23, while also a lager strain, can contribute subtle fruity notes (pear, apple) and a slightly fuller body, making it versatile for European lagers seeking a nuanced character. My experience confirms both perform admirably under strict temperature control.

The Brewer’s Hook: Navigating the Lager Yeast Divide

For two decades, my life has revolved around the controlled chaos of fermentation, coaxing grains and hops into liquid gold. Among the most rewarding, yet challenging, styles are lagers. When I first started experimenting with them, I’d often grab a generic “lager yeast” and cross my fingers. That was a mistake. I learned quickly that the subtle nuances between strains like Saflager W-34/70 and S-23 are not just theoretical; they fundamentally shape the beer in your glass. My journey with these two particular strains has been a fascinating exploration of precision brewing, and I’ve come to understand their distinct personalities through countless trials and detailed fermentation logs. Let me share what I’ve discovered.

The Math Behind My Fermentations: Pitching Rate & Attenuation

Precision in brewing, especially with lagers, starts long before the yeast hits the wort. It begins with the numbers. I meticulously calculate my pitching rates and track attenuation because these metrics are non-negotiable for producing consistent, high-quality lagers. Generic recommendations often fall short for the serious homebrewer; I rely on specific formulas.

Yeast Pitching Rate Calculation

For lagers, underpitching is a cardinal sin, often leading to sluggish fermentations, diacetyl, and off-flavors. My standard for a healthy lager fermentation is 1.5-2.0 million cells/mL/°Plato for a standard gravity lager (12-15°P), or up to 3.0 million cells/mL/°Plato for high-gravity brews. Dry yeast packets typically contain 11.5g, which I estimate contains about 200 billion viable cells. However, viability decreases over time, so I adjust for storage. For fresh packets, I use 200 billion.

Here’s my go-to formula for calculating the required cells (assuming 11.5g dry yeast packet):

Required Cells (billions) = (Target Pitch Rate (million cells/mL/°P) * Wort Volume (L) * Original Gravity (°P)) / 1000

Let’s use an example from my brew log: A 20-liter (approx. 5.28 US gallons) batch of a Helles with an OG of 12°P (1.048 SG) using W-34/70, targeting a 1.8 million cells/mL/°P rate:

Required Cells = (1.8 * 20 * 12) / 1000 = 432 / 1000 = 0.432 billion cells

Wait, that’s incorrect for ‘billions’. Let’s adjust the formula for direct use:

Required Cells (total) = Target Pitch Rate (cells/mL/°P) * Wort Volume (mL) * Original Gravity (°P)

For the same example:
Required Cells = 1,800,000 cells/mL/°P * 20,000 mL * 12 °P = 432,000,000,000 cells = 432 billion cells.

Since one fresh 11.5g packet is roughly 200 billion cells, I would need 2.16 packets (432 billion / 200 billion) for this specific brew. I always round up, so 3 packets for this. This level of precision, while seemingly obsessive, is what separates a good lager from a great one.

Apparent Attenuation (AA) Calculation

Apparent Attenuation tells me how much sugar my yeast has converted. It’s crucial for predicting final gravity and ABV.

AA (%) = ((OG - FG) / (OG - 1.000)) * 100 (using specific gravity readings, converting 1.000 to 0)

Let’s say my Helles started at an OG of 1.048 and finished at an FG of 1.008 with W-34/70:

AA (%) = ((1.048 - 1.008) / (1.048 - 1.000)) * 100
AA (%) = (0.040 / 0.048) * 100 = 0.8333 * 100 = 83.33%

This 83.33% attenuation for W-34/70 is right in line with my expectations for a dry, crisp lager.

Step-by-Step Execution: My Lager Brewing Process

My approach to brewing lagers with W-34/70 or S-23 is nearly identical up to the pitching stage, but the fermentation schedule diverges significantly.

Pre-Fermentation: Precision is Paramount

1. Milling & Mashing: I aim for a fine crush to maximize efficiency. My typical lager mash schedule is a single infusion at 65°C (149°F) for 60 minutes, followed by a mash out at 76°C (169°F) for 10 minutes. This provides enough fermentable sugars for a dry finish while retaining some dextrins for body. pH control is critical; I target a mash pH of 5.2-5.4.
2. Lautering & Sparging: Slow and gentle. I usually sparge with water at 77°C (171°F) to avoid extracting tannins.
3. Boiling & Hopping: A vigorous 90-minute boil is standard. For a Helles (my typical W-34/70 vehicle), I’d use noble hops like Hallertau Mittelfrüh, targeting 20-25 IBU. For an International Pale Lager (my S-23 choice), I might go with Magnum for bittering and Saaz for aroma, hitting 25-30 IBU.
4. Chilling: This is where precise temperature control becomes paramount. I use a plate chiller to rapidly bring my wort down to pitching temperature. For W-34/70, I chill to 10°C (50°F). For S-23, I go slightly warmer, to 12°C (53.6°F). Accurate temperature measurement here is non-negotiable.

Fermentation Schedules: W-34/70 vs. S-23

This is where the rubber meets the road. These aren’t just recommendations; these are the schedules I’ve refined over years for each strain.

My W-34/70 Fermentation Schedule (Clean Lager Focus)

1. Pitching: Hydrate 2-3 packets (depending on OG, see math above) of W-34/70 in 100ml of sterile, 25°C (77°F) water for 15 minutes. Pitch into wort at 10°C (50°F).
2. Primary Fermentation: Maintain 10-11.5°C (50-52.7°F) for the first 7 days, or until gravity drops to approximately 1.015 (around 70% attenuation). This cooler temperature suppresses ester production, leading to a crisper profile.
3. Diacetyl Rest: Once primary fermentation slows, I slowly ramp the temperature up to 14°C (57.2°F) over 24 hours. I hold this temperature for 2-3 days. A VDK (vicinal diketone) forced diacetyl test confirms readiness.
4. Cold Crash/Lagering: After a successful diacetyl rest, I rapidly cool the beer to 0-2°C (32-35.6°F). I transfer to a serving keg or secondary fermenter (if needed for dry hopping, which is rare for my lagers) and lager for 3-6 weeks. My preferred lagering temperature is -1°C (30.2°F).

My S-23 Fermentation Schedule (European Lager/Fruity Nuance Focus)

1. Pitching: Hydrate 2-3 packets of S-23 similarly to W-34/70. Pitch into wort at 12°C (53.6°F).
2. Primary Fermentation: Maintain 12-13.5°C (53.6-56.3°F) for the first 5-6 days, or until gravity drops to approximately 1.018 (around 65% attenuation). Slightly warmer than W-34/70, this allows for the characteristic subtle fruity notes to develop without becoming overpowering.
3. Diacetyl Rest: Slowly ramp the temperature up to 16°C (60.8°F) over 24 hours. Hold this temperature for 3-4 days. S-23 often benefits from a slightly longer diacetyl rest due to its more characterful profile.
4. Cold Crash/Lagering: Rapidly cool to 0-2°C (32-35.6°F). Transfer and lager for 2-5 weeks at 0°C (32°F). S-23 generally clarifies well, but sometimes benefits from an extra week of cold conditioning.

Throughout both processes, I’m taking daily gravity readings and constantly monitoring temperature. Consistency is key, and I often refer back to the extensive resources available on BrewMyBeer.online for troubleshooting specific issues or exploring new techniques.

What Can Go Wrong: Troubleshooting Common Lager Issues

Even with meticulous planning, brewing lagers can present challenges. Here are the issues I’ve most frequently encountered and my tried-and-true solutions.

• Diacetyl (Buttery/Butterscotch Off-Flavor): This is the bane of lager brewers. Almost always due to insufficient diacetyl rest.
  • My Fix: After primary fermentation, raise the temperature to 15-18°C (59-64°F) for 2-5 days. Perform a forced diacetyl test (take a sample, heat it in a covered jar to 60°C for 10 minutes, cool, and sniff) to confirm it’s gone. If not, extend the rest. For S-23, this is particularly important.
• Slightly Fruity/Estery Profile (for W-34/70): If my W-34/70 lager has hints of apple or pear, I know I fermented too warm.
  • My Fix: The only solution for future batches is stricter temperature control during primary fermentation. I ensure my fermenter’s external temperature probe is well-calibrated and often immerse it in a thermowell for direct wort temperature readings.
• Stuck Fermentation: Gravity stops dropping prematurely.
  • My Fix: First, ensure the temperature is within the yeast’s optimal range (e.g., 11.5°C for W-34/70). Gently rouse the yeast by swirling the fermenter. If it’s still stuck, I might raise the temperature slightly (1-2°C) to wake up the yeast. Underpitching or insufficient nutrients are common causes, so I review my initial calculations.
• Sulfur/Phenolic Off-Flavors: Particularly noticeable in the early stages of W-34/70 fermentation (rotten egg smell).
  • My Fix: This is often normal with W-34/70 and usually cleans up during the diacetyl rest and lagering. If it persists, ensure adequate yeast health, proper pitching rates, and sufficient lagering time. Very high pitch rates or insufficient oxygenation can exacerbate this.
• Poor Clarity: Hazy lager despite lagering.
  • My Fix: Ensure a good cold crash (0-2°C) for at least 48 hours before transfer. Longer lagering at near-freezing temperatures (-1°C) usually resolves this. A fining agent like gelatin (1/2 tsp dissolved in 1 cup hot water, cooled to 30°C, added to cold beer) can work wonders, but I prefer natural conditioning when possible.

Sensory Analysis: My Preferred Outcomes

After all the precision, the proof is in the pint. Here’s how I expect my beers to present themselves when brewed with W-34/70 and S-23 under my specified conditions.

W-34/70: The Epitome of Clean

• Appearance: Brilliant, crystal-clear golden to pale straw color, reflecting the finest German Pilsner malt. Forms a dense, persistent white head with fine bubbles. My ideal SRM for a Helles with W-34/70 is 3-4.
• Aroma: Dominated by clean malt sweetness reminiscent of fresh bread or subtle honey. Hop aroma (if noble hops are used) is delicate, floral, or spicy, never overpowering. Absolutely no fruitiness or solvent notes. A whisper of sulfur early in fermentation that vanishes.
• Mouthfeel: Crisp, effervescent, and medium-light body. Extremely clean finish, leaving the palate refreshed. No cloying sweetness or harsh bitterness. Carbonation is typically 2.5-2.7 volumes CO2.
• Flavor: Balanced and harmonious. A gentle bready or slightly malty sweetness upfront quickly gives way to a firm, noble hop bitterness. The finish is dry, clean, and utterly refreshing. The hallmark is its complete lack of yeast character, allowing malt and hops to shine.

S-23: The Characterful European

• Appearance: Clear golden to amber, perhaps slightly less brilliant than W-34/70 due to its slightly lower flocculation. A good, creamy white head. My typical SRM for an International Pale Lager with S-23 is 5-7.
• Aroma: A pleasant, subtle blend of malt sweetness and a distinct fruity character – often green apple, pear, or a hint of berry, especially if fermented slightly warmer. Hop aroma can be more pronounced, playing well with the yeast esters. I detect a faint whiff of caramel if I’ve used some Munich malt.
• Mouthfeel: Medium body, often feeling slightly fuller than a W-34/70 lager. Carbonation is smooth, usually 2.4-2.6 volumes CO2. The finish is clean but might carry a very light fruitiness that lingers momentarily.
• Flavor: Begins with a balance of malt and a gentle fruitiness. The hop bitterness is present but often complemented by the yeast character. It’s a more complex, less austere lager experience, leaning towards the “European Lager” profile rather than strictly “German.” It often finishes with a soft, lingering fruit note rather than the hard crispness of W-34/70. This yeast never leaves a sticky residual sweetness in my experience, but definitely a more rounded profile.

Frequently Asked Questions About Saflager Yeast

Are W-34/70 and S-23 interchangeable in recipes?

Absolutely not. While both are lager yeasts, my experience shows they yield distinctly different flavor profiles. W-34/70 excels at producing very clean, neutral, malt-forward lagers, true to classic German styles. S-23, on the other hand, imparts noticeable fruitiness (often pear or green apple) and a slightly fuller body, making it more suited for European lagers where a touch of yeast character is desired. Swapping them without accounting for these differences will drastically alter your final beer.

Can I ferment W-34/70 or S-23 at ale temperatures?

Technically, yes, you can, but it’s not something I recommend for quality lager production. My trials show that W-34/70 fermented at, say, 18°C (64°F) will produce a significant amount of sulfur and a much more pronounced, though still relatively clean, ester profile that detracts from its crisp lager character. S-23 fermented warm (above 18°C) will amplify its fruity esters to a level I find distracting, often tasting like an unbalanced ale or even a cider. If you want a clean ale, use an ale yeast. The entire point of these lager strains is their performance at lower temperatures.

How do I ensure good clarity with these lager yeasts?

Both W-34/70 and S-23 flocculate well, but lagers naturally benefit from extended cold conditioning. My process involves a rapid cold crash to 0-2°C (32-35.6°F) after the diacetyl rest. Then, I lager the beer at near-freezing temperatures, ideally -1°C (30.2°F), for a minimum of 3-4 weeks. This extended period allows all yeast, proteins, and polyphenols to drop out of suspension. If I’m truly pressed for time or have a stubborn haze, I sometimes use a fining agent like gelatin, but patience is usually the best approach for superior clarity.

What about re-pitching or harvesting these dry lager yeasts?

I frequently harvest and re-pitch both W-34/70 and S-23. The key is careful sanitation and handling. After primary fermentation, I typically rack the beer off the yeast cake, then either collect the healthy yeast from the bottom of the fermenter or rinse it gently. For my next batch, I calculate a fresh pitching rate and inoculate with the harvested slurry. I usually limit re-pitching to 5-7 generations to maintain consistent performance and avoid potential genetic drift. Always check for off-flavors or signs of infection in the parent batch before harvesting; a bad batch means a bad harvest. For more detailed guides on yeast handling, I always consult reliable sources like BrewMyBeer.online.