The story 2022 Spring to 2023 winter

 

Shinjuku Golden Gai — a small corner of the city where the charm of the Showa era meets the modern day.
In 2015, we opened OPEN BOOK, a bar specializing in lemon sours.
With the hope of bringing the refreshing tartness and fresh flavor of our in-store lemon sours to more people, we launched our take-home version, Real Lemon Sour, in 2021.

At OPEN BOOK, our lemon sours evolve with the seasons, allowing you to enjoy different flavor profiles throughout the year.
This article looks back on the journey from the debut of Real Lemon Sour in spring 2022 to the winter 2023 edition — one year of continued refinement and flavor innovation.

 

Spring 2022

 

This marks the final batch of lemon sour for the season.
Calling it “this year” might be a bit misleading, as it actually refers to the end of the lemons harvested since last autumn. Regardless of the calendar year, this is where we draw a line for now.
The next batch of lemons, grown from saplings planted around this time, will be ready for harvest in the following autumn—signaling the start of a new season.

By now, the lemons have fully ripened—bright yellow, large, and brimming with flavor.
It’s always a little sad to say goodbye, but if we wait too long, the lemons risk sunburn and a loss of freshness. So this really feels like the right time to make the final batch.

This was our fifth round of production, and we’re definitely starting to get the hang of it.
Thanks to Mr. Suga, the farmer we work with, the lemons are delivered right on our scheduled prep day, ensuring they arrive as fresh as possible.
We peel them in small batches and immediately begin infusing them—never waiting more than a few hours. Since the essential oils in the peel are crucial to the flavor, maintaining that freshness is our top priority.

After soaking, we monitor the flavor closely and usually remove the peels after about two days.
By the way, the rest of the lemons (aside from the peels) are fully juiced and used in our regular syrup products.
We add the syrup to the base little by little, tasting along the way.
This time, we ended up using the entire batch of syrup we had prepared.
From our experience, when the lemon aroma and acidity are strong, we can afford to add more syrup. Just like in winter, the lemon flavor transferred beautifully.

As for the alcohol, we used a premium sake from Tomita Sake Brewery this time.
You should be able to taste the rich notes of brown sugar and koji in the finish.

One special touch this time—we sealed the bottle cap with wax.
Of course, it’s all done by hand.
You might be momentarily confused about how to open it, but don’t worry—it’s a screw cap underneath. Just give it a good twist through the wax, and it should open right up.

Thank you for enjoying it with us.
—Tanaka

 

 

 

 

Winter 2023

At OPEN BOOK, we make lemon sours across three seasons: autumn, winter, and spring.
Although the Autumn 2022 batch hasn’t been released yet, we’ve decided to let it rest a little longer and release Winter 2023 first.

Each batch is created with a seasonal theme that highlights a different personality of the lemon.
This time, the focus is acidity.

One major change in this year’s recipe is the addition of lemon juice.
Surprisingly, until now, we had never included juice in our lemon sours.
That’s because juice tends to oxidize quickly, doesn't contribute much aroma, and mainly just adds sharp sourness.
We were unsure how that would affect the overall balance and how it would interact with the aroma and depth of the shochu.

Here’s a look at the manual juicing process we used this time..

To be honest, last year’s winter lemon sour wasn’t bad, but compared to the spring version, I felt the acidity lacked depth and complexity.

On the other hand, spring lemon sours benefit from peel oils being at their peak—this brings out a rich, vibrant flavor even with a simple recipe.

If I’m being blunt, the winter version came across as a slightly inferior version of spring.

This time, I wanted to take it in a different direction.

So I chose acidity as the key theme—contrasting with the bitterness of autumn and the umami of spring.

We freshly peeled and juiced the lemons on the spot, adding everything directly into the tank.

As a result, the acidity is a bit sharper—similar to the kind of punchy, freshly squeezed lemon sour you’d get at an izakaya, like Ban in Yutenji.

That said, this version lacks the familiar sweetness of OPEN BOOK’s usual style.

When we serve it at our bar, we often add syrup—about 5ml per 100ml—as a final touch.

So depending on your taste, we recommend trying it with a little syrup added.

In the end, what we created is a pure, classic lemon sour base—something that might be considered a “universal” lemon sour flavor.

Personally, I still wish it could’ve been even more sour or had more cooling freshness.

But that’s something to look forward to improving next year.

—Tanaka

 

Autumn 2022

 

This batch was made in November 2022 and released in July 2023, so there’s been quite a gap between production and sale.

As with every autumn release, this lemon sour has a refreshing, crisp taste that captures the vibrant green character of early-season lemons.

Compared to our usual OPEN BOOK lemon sours, this one is a bit lighter and less sweet—making it a perfect pairing with food.

At our bar, when serving the Autumn Lemon Sour, we usually add a little extra syrup to balance things out.

If you find it a bit too dry, feel free to add some syrup yourself—and if possible, we recommend using our house-made lemonade syrup.

Starting with this batch, the labels are now made from hand-crafted Japanese washi paper.

They’re made by a friend of mine—someone my age—who’s helping to preserve traditional crafts in Saga Prefecture. The paper is from Nao Tesuki Washi, and it looks fantastic.

Also, you may have noticed… the price has gone up slightly again.

We’re truly sorry.

Due to the recent wave of price increases everywhere, we've been affected too.

That said, with upgrades like the washi label and overall improved quality, we hope you'll understand and continue to enjoy our product.

—Tanaka

 

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