Hello I’m Andrea Castillo and this is Seasonal, a newsletter that connects you to the Bay Area food system, one fruit and vegetable at a time. Seasonal comes out twice per month, and each post highlights the most interesting aspects of one seasonal fruit or vegetable grown and harvested around the Bay Area. Find me on Instagram at @seasonalbayarea or e-mail me at to share your feedback and suggestions, I’d love to hear from you. If you’d like to unsubscribe, click the gray unsubscribe link at the bottom of this post.

Winter is a great time of year for citrus in the Bay Area. For this bonus February post, we nerd out on grapefruits (available December-April). 


I have to admit, I thought grapefruits were either yellow or pink inside and that was essentially the difference between varieties. But Jake, the friendly staff member working at the Sunrise Farms stand at the Temescal farmer’s market proved me wrong. To demonstrate the difference between the rio and marsh grapefruits on the table, he cut them up for a taste. The juicy, sour-patch-kid tart, red rio grapefruit and the even juicier, sweeter, yet still acidic marsh couldn’t have been more different. Jake then offered a melogold and oro blanco tasting. The sweetness of these two was the perfect contrast to the first tasting and the diverse world of grapefruit suddenly became real.

From left to right: rio, oroblanco, marsh, and melogold grapefruits, all grown by Sunrise Farms in Orosi, 45 minutes southeast of Fresno. If you zoom in or squint a bit, you can see the letters the staff member carved into each grapefruit to help me remember which one was which.


For some bizarre psychological reason based on no facts whatsoever, I expected the red rio grapefruit to be the sweetest of all four during the tasting and was surprised it was so tart. It turns out that the color of a grapefruit has nothing to do with its taste, but a lot to do with its health benefits. The red grapefruit variety has a slight health advantage over its white or yellow counterpart. Similar to tomatoes and guavas, red grapefruits have beta carotene and lycopene, which are both powerful antioxidants that the white and yellow fleshed grapefruits lack. With their high vitamin A and C content and the bonus antioxidants, red grapefruits were starting to seem like they could be contenders for superfruits. But then I remembered how my father and I have never been able to enjoy grapefruits together because of his high blood pressure.

You might think that avoiding grapefruit because of high blood pressure is an old wives’ tale, but it’s a real health issue. Grapefruits and prescription drugs that lower high blood pressure don’t play nice together. Grapefruits have naturally occurring organic chemical compounds called furanocoumarins that throttles our intestines’ working speed from normal to turbo. When this happens, intestines over-absorb blood pressure drugs into our blood stream, essentially triggering a potential overdose. who. knew! So, before biting into a grapefruit, triple check those prescription bottles or ask your doctor about grapefruit.

at the market

If you and grapefruits can safely interact, then here are a few ways to find the best ones. When picking grapefruits, scratch the skin a bit to ensure they smell bright and citrusy, avoid blemishes on the skin, go for ones that feel heavy for their size (heavy indicates juicy), and buy organic so you can use the whole fruit. At the farmer’s market, ask to taste the different kinds on offer to get a better idea for tartness, sweetness, and juiciness between them. And while you’re at it, ask them to help you pick the best one if you’re struggling on which one to pick. I’m sure they’d be more than happy to help.

reducing waste

To get the most out of grapefruits and prevent unnecessary waste, keep them on the counter for up to a week without stacking too many on top of each other. If overstacked, all that weight can bruise and damage the fruit. Do not keep grapefruit in bags or air tight containers, they need airflow to stay healthy and mold free. Alternatively, grapefruits can be stored in the refrigerator for up to three weeks, but take them out well before eating, because they taste best at room temperature.

Got a bitter and tart grapefruit? Don’t chuck it! Bitter and tart grapefruits taste great if you eat them the way I used to when I was a little kid: sprinkle a little salt on them. I never knew why I liked that combination so much, but there’s fun science behind this pairing: salt ions block the bitter receptors in your tongue, thus allowing some of the sweetness in the fruit to shine. 

To use up the whole fruit, try making candied grapefruit peel: if you’re running low on time, store the peels in the fridge so you can do a batch of candied peels a day or two later. A different way to use the peel is to zest the grapefruit before cutting into it. Leave out the zest to dry overnight to make grapefruit salt later on.

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Andrea Castillo is a food nerd who always wants to know the what’s, how’s, when’s, and why’s of the food she eats.