Espresso = mc²? Researchers apply math and physics to espresso extraction. Plus, Philz Coffee removes pride flags from all its locations, and negotiations remain tense between Starbucks and its union.
‘Bay Area Institution Philz Coffee To Remove Pride Flags From All Cafés’ – via San Francisco Chronicle
Philz Coffee, the San Francisco-based specialty chain, is removing Pride flags from all its stores.
It is unclear when the decision to remove the flags was first made. Last week, a Change.org petition began circulating on social media, urging Philz’s leaders to reconsider.
The petition, signed by “Philz Coffee Baristas,” says that “the Pride flags within the stores hold deep meaning and value to both staff and visitors, symbolizing that these locations are safe and welcoming spaces for all individuals, regardless of sexual orientation or gender identity.”
However, the company’s CEO, Mahesh Sadarangani, doubled down on the decision. In an emailed statement to the San Francisco Chronicle, Sadarangani said Philz “was working toward creating a more consistent, inclusive experience across all our stores, including removing a variety of flags and other decor.”
As of April 8, Pride flags and other decorations were still on display at one San Francisco location. Employees at two other Philz stores told the Chronicle they hadn’t heard of the new rule.
Philz has been a Bay Area institution since its founding in 2003 by Phil and Jacob Jaber. The brand grew to nearly 70 locations in California and Illinois on the back of significant venture capital investment. The Jabers stepped back from running the company in 2021, with Sadarangani taking over as CEO. In August 2025, Philz was acquired by the private equity firm Freeman Spogli & Co.
In his emailed statement, Sadarangani said that Philz’s “longstanding support of the LGBTQIA+ community is unchanged. This is a change in how our stores look, not in who we are.”
In response to the news, members of the Oakland and San Francisco LGBTQ+ cultural districts wrote an open letter expressing their “extreme disappointment” with Philz. “When Philz came to our neighborhoods, it did so knowing it would be serving our communities,” the letter reads. “These recent actions, however, suggest that you do not prioritize us or the diversity of the LGBTQ community.”
Read the full story on the Pride flag removal here.
‘Having Trouble Dialing In? There’s An Equation For That’ – via Sprudge
Dialing in espresso to produce a tasty shot is a tricky and often laborious process. Anyone who has worked behind the bar or wrangled with their home espresso machine can attest to how many times they have had to adjust their grind and pull shots to get espresso to taste just right.
When fiddling with a grinder, making the settings finer slows the rate at which water can move through the grounds; a coarser setting does the opposite. But how exactly do those grind changes impact what’s happening within the portafilter? An international team of scientists decided to find out.
The study, published in the journal Royal Society Open Science, investigated how various grind sizes can impact puck permeability (or how water moves through ground and tamped espresso) and extraction. To do this, the researchers ground two different coffees at 11 grind settings, ranging from fine to coarse. They then packed the samples into tubes and used X-ray computed microtomography to create a 3D map of each sample.
The maps allowed the researchers to see the internal structure of each sample, including all the little hidden passageways and rivulets known as pore spaces—these create paths for water to move through an espresso puck. They then ran digital tests to see how grind size impacted water flow. With this data, they were able to create a mathematical equation that predicts how well a shot might pull based on grind size and tamping.
“We have proposed and validated a constitutive model for the permeability of beds/pucks of ground coffee,” the authors wrote in their conclusion. They also note that other factors, like oxidation and coffee staling as it ages, and how the grounds expand when in contact with water, can impact permeability and require further investigation.
Read more on the espresso equation here.
More News
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‘The Top 10 US Cities for Coffee, According to the Experts’ – via Food & Wine
‘Bialetti Promotes Global Celebration of the Moka Pot’ – via Global Coffee Report
‘Colombia’s Coffee Production Falls 36% in February to 869,000 Bags’ – via StoneX
‘Labor Department Recovers $85,197 for Workers at Texas Coffee Bar’ – via Daily Coffee News
The Week in Coffee Unionizing
Negotiations between Starbucks and union representatives stalled last year. But in February, Starbucks Workers United submitted a contract proposal to the company in an effort to restart the bargaining process. Now, according to Josh Eidelson at Bloomberg, the union has filed an unfair labor practice charge with the National Labor Relations Board, accusing Starbucks of negotiating in bad faith.
The complaint alleges that Starbucks backtracked on seven items to which it had previously agreed, and presented “punitive” proposals that the union could not accept. The union accused Starbucks of negotiating “with the intent of preventing any agreement from being reached.”
Starbucks spokesperson Jaci Anderson denied the allegations, saying that the company was bargaining in good faith and had put forward “comprehensive proposals that build on our already-competitive pay and industry-leading benefits.”
“Starbucks has returned to the bargaining table, but its behavior hasn’t improved,” SBWU wrote in a statement. “Union baristas are committed to landing a fair deal and, at the same time, we aren’t afraid to call out Starbucks’ illegal actions.”
Meanwhile, following in the footsteps of their colleagues in New York City and Boston, the workers at Blank Street Coffee in Washington, D.C., have announced their intent to unionize. According to an April 8 Instagram video, workers at the company’s two D.C. locations decided to organize because, while they love their jobs, “we are being exploited for our love.” They cite low wages, inconsistent hours, and overwork as reasons for unionizing.
“We believe that Blank Street Coffee will thrive best when staff can buy into goals and policy, making thoughtful collaboration an integral part of the process,” one of the unionizing baristas says in the video. “We also want to ensure that our own needs are met so that we can come to work with dignity.”
Is Coffee Good For You?
Moderate coffee or tea consumption may lower your risk of developing lung cancer, according to a recent study from China.
The study, published in Frontiers in Nutrition, used data from the U.K. Biobank biomedical database to track the coffee and tea consumption of more than 275,000 participants over more than a decade. Researchers compared the data to incidences of lung cancer, adjusting for demographic and other lifestyle factors like alcohol intake and smoking.
They found that, compared to non-coffee drinkers, those who reported drinking between half a cup and one cup of coffee daily had a 28% lower risk of developing lung cancer, while those who drank 2-3 cups per day had a 23% reduced risk. Drinking tea was also associated with a lower risk of developing lung cancer.
The authors noted that their study had some limitations, including that coffee intake was self-reported and collected only once at the beginning of the study period. Additionally, participants were mostly of European ancestry, making it difficult to generalize the results to other populations. “Further studies are needed to validate these findings across different ethnic populations and elucidate the underlying biological mechanisms,” the authors concluded.
We often report on studies like these, and in doing so, we find that they contradict one another. For example, the findings above contradict research from 2019 that linked drinking coffee to a higher risk of developing lung cancer.
In that study, the researchers looked at data from 1.2 million participants in the United States and Asia. They found that coffee drinkers had a 41% higher chance of developing lung cancer than non-coffee drinkers—and the risk increased even further for decaf drinkers.
We look forward to a future study that contradicts the latest research, and then another one that contradicts that one, and so on forever. Maybe we’ll have a cup of coffee while we wait.
Beyond the Headlines
‘We Asked For Your San Diego Coffee Recs. We Got Over 100 Responses.’ by Ashley Rodriguez
‘Opinion: Technical Gap Slowing Agroforestry in Key Colombian Lands’ by Juliana Cajiao Raigosa
