15 questions to ...
15 Questions to …is an interview series dedicated to spotlighting women in entrepreneurship. Women entrepreneurs question the status quo and lead change. They push boundaries and leave their marks on all aspects of (entrepreneurial) life. As such, they are strong role models who inspire and empower future generations of women and deserve to be seen and heard. We see women entrepreneurs in all areas of our community and want to make sure they are recognised far beyond the RWTH Aachen University ecosystem.
Therefore, we are leaving the stage to hear what they have to say. The format is simple: 15 questions, 15 answers – and lots of (un)learning throughout. Our guests: women entrepreneurs with that special can-do and will-do attitude. The stage is yours!
Sarah & Lisa Nesti

Sarah and Lisa Nesti are not just CEO and CMO, but also co-founders of The Oater, an innovative start-up aiming to revolutionize milk alternatives. Their innovation lies in creating appliances for local production of oat-based milk substitutes, minimizing packaging waste and transportation emissions through a hyper-local approach. The start-up's primary objectives include the expansion of their Barista oat drink solution to cafes across major cities, the promotion of local and sustainable production, and the ambitious goal of saving 1 billion kg of CO2 by 2030 to significantly reduce future CO2 emissions. Originating in RWTH Aachen's ecosystem, the start-up participated in the RWTH Incubation Program's Spring Batch 2023. The team continues to be active within the Aachen start-up ecosystem despite having relocated the company to Cologne since. Recently, The Oater concluded a seven-digit pre-seed funding round with notable investors, propelling their vision. Today the sisters share their entrepreneurial adventure with us.
1) Why our idea is going to change the world?
Our company, The Oater, is set to transform the milk substitute market by offering unparalleled product quality, freshness, and taste while addressing environmental concerns. Through our innovative "Oat Drink as a Service" model, we empower the food services industry with sustainable, locally-produced oat drinks, leading the charge towards reducing packaging waste and carbon emissions, ultimately revolutionizing how plant-based alternatives are experienced, consumed and embraced. Our approach of hyper-localizing oat drink production is just the first step in revolutionizing the food value chain. This concept can be applied to many other contexts.
2) Did you choose it or did it choose you?
It chose us. None of us had ever considered entrepreneurship as our career path, but looking back, we had always had new ideas and big dreams since we were kids. Our founding journey began in 2021 when Sarah, who has been vegan for 7 years, was annoyed by all the packaging waste and the lack of freshness of her oat milk. She tried all the alternatives to regular oat milk from the carton, but none convinced in taste or foam. Her conclusion: good barista oat milk without packaging waste? There is no such thing! As an engineer, she figured there had to be a better way and assembled a team to find a solution including her sister Lisa. And here we are less than 2 years later with a fully functional product entering the market!
3) Biggest challenge on our entrepreneurial journey so far:
Learning how to manage our energy and well-being. We have been challenged to understand how we recharge best to make our entrepreneurial journey a marathon and not a sprint. It is key to figure out what works best for you. You need energy to channel productively into building your vision.
4) Lessons we have learned as founders:
Start-ups are never built alone. Our team is our most important asset. The start-up journey is an intense experience and having a team that supports and leans on each other is crucial. We invest heavily in building a culture within our founding team and beyond based on trust, ownership and care. Also, no one always knows what they are doing. Learn, reiterate and grow continuously rather than compare yourself to your perception of others. Be bold, curious, and (way) kinder to yourself.
5) We financed ourselves...
We raised angel investment early on in our start-up journey to develop our product and grow quickly. Additionally, we have benefitted from different public grants and programs, such as the Women Tech EU grant.
6) 5 years from now we will …
transcend our roots, expanding beyond Barista oat drinks to pioneer on-site plant-based food experiences across diverse domains. Fueled by our patent-backed vision, we'll infuse the $123 billion vegan milk market with innovation and compassion, creating a tapestry of taste and values that enriches lives and nourishes souls, marking a new era in food innovation by 2030.
7) If we weren’t founders, we would be …
coming up with big ideas in the most random moments and places.
8) What do I need to be a successful entrepreneur?
You need courage and passion for what you’re working on to keep going through the rollercoaster that is the entrepreneurial journey. But beyond that there is not one mold that fits all – be authentically you. This is how you will inspire others to help you build your vision.
9) RWTH Innovation helped us with …
finding tech-oriented investors and partners!
10) Is there anything more that could be done for entrepreneurs in Aachen?
We would like to see more international exchange and collaboration since new impulses and different perspectives are the basis for innovation. On that note, we would also love to see more diversity and heterogeneity among the founders!
11) 3 reasons to become an entrepreneur:
- Positive change and environmental impact
- Personal fulfillment and purpose
- Growth and continuous learning
12) To us being an entrepreneur means …
courageously and collaboratively translating ideas into impactful ventures, driven by authenticity, purpose, and a commitment to positive change.
13) My favourite digital tool:
Asana – It enables us to bring structure and efficiency into our interdisciplinary projects.
14) I am are inspired by / my role model is …
my sister.
15) Our advice to women who aspire to be entrepreneurs:
Get started! Don’t let your self-doubts and insecurities keep you from building something great. Find mentors and create a support system for yourself that embraces you the way you are.