The Almighty Kumquat

Kumquats_KWBarnes_05Chances are, if you’re a home brewer, you have a particular style and ingredient you enjoy most. For me, it’s the saison and a sour citrus fruit that I didn’t truly discover until I read Randy Mosher’s Radical Brewing. In his book, Mosher described a stand-in for the Seville Orange, a citrus which is traditionally used by Belgian brewers in Witbier and other spiced ales. Seville, or bitter oranges, are also the primary ingredient in Southern marmalade. As cool and traditional as these oranges are, they can be difficult to find in Southern California and so Mosher suggests the use of whole kumquats as a stand in. The kumquat mimics the sweet, bitter, and sour elements of a bitter orange very closely, but also adds flavors of its own, which I find irresistible. What’s more, despite this hybrid citrus tree’s southeast Asian origin, it’s abundant in Southern California and performs quite well just like its citrus industry brethren.

Since starting my home brewing adventure in 2009, my favorite style to brew, Saison, has been a perfect vehicle for this fruit. I appreciate the style’s flexibility and diversity. Like many other Belgian beer styles, there isn’t one correct variation, but instead a wide sprawling category that envelopes beers of all strengths, colors, and flavors. From dry to sweet, from spiced to virgin, from light to dark, Saison runs the gamut. Most brewers tend to edge towards a golden drink with funky, farmhouse, barnyard aromas, which are often accentuated by the addition of citrus and spices. The saison I brew, originally called Equinox, now Lievre, is a dry, spiced, 7% ABV saison utilizing a custom belgian/french saison yeast blend.  When I first brewed this beer I used a combination of grapefruits and Valencia oranges, but since my discovery of the kumquat in 2010, it’s been very hard to use anything else. I think you’ll find that for a citrus saison, lambic, or any beer for that matter, kumquats add a complexity that far surpasses oranges, grapefruit, or combinations of the two.


Prepping Kumquats for Brewing

There are quite a few ways to prepare kumquats for use in beer, but I’m going to outline the method that I find produces the best flavor and results. For this method you’ll need to do little more than harvest, clean, sanitize, bag, and freezel

Fresh Harvest

Kumquats can definitely be found at the store, but the sacrifice to quality and the pocket book may not be worth it. Store bought kumquats are harvested underripe and so many have not had the time to develop their full flavor potential. These kumquats are incredibly expensive especially when factoring in the amount you’ll need for brewing.  Store bought kumquats are homogenized and so individual tree character is lost when using them.  This character is important when brewing on the home brew level and is a luxury that commercial side can’t fully take advantage of.  For example, I harvest many of my kumquats from a tree my friend, Aielo, owns and the fruit from this tree in particular has a spectacular pineapple, coconut, citrus quality.  Pina Colada kumquats anyone?


The best method for getting Grade-A kumquats is to find them wild, or rather in your neighbors backyards (thanks Aielo!). Lucky for brewers, kumquats are one of those fruits that people just don’t know how to use and so they tend to rot on the tree, ignored. In addition, these trees, when harvested regularly will fruit multiple times a year, which makes it even easier to stockpile for brew day.

When harvesting kumquats don’t be afraid to be picky. Soft, severely blemished, rotten, and/or shriveled kumquats should be avoided. The fruit should be plucked from the tree without tearing the top. Pulling part of the branch off with a few leaves is better than exposing the inner fruit to the open. Note: This may not be the best method for the tree, but it’ll ensure that your fruit can be cleaned thoroughly.


Aielo Jimenez in front of his 35 year old Kumquat tree



I find doing a pre-rinse prior to the main cleaning session works really well. I collect all of my kumquats in large rubbermaid bins and then spray them down with water one colander full of fruit at a time. If you do this over your bins you can collect the water and dump into a rain barrel to reduce waste.

After the pre-rinse, use a vegetable wash (I use Trader Joe’s brand Fruit & Vegetable Wash) to remove the dirt. To do this, fill a large mixing bowl half way with water, use a few tablespoons of Vegetable Wash and give the fruit a soak for about a minute. Move the fruit around with your hands lightly scrubbing each kumquat with your fingers.  Transport the fruit to a colander and rinse thoroughly while saving the vegetable wash for the next batch of fruit.


Use a final rinse sanitzer like star-san. In another large mixing bowl, fill halfway with water, and add star-san to the proper beer dilution. Using a little over the recommended dosage wont hurt anything, but be sure to wear rubber gloves to reduce the impact on your hands. Soak the kumquats in the sanitizer bath for approximately 60-90 seconds and then transport them to a sanitized colander to drip drain for another 60 seconds.



The fruit can now be moved to gallon sized freezer bags, you can fit approx. 5 pound in each bag, which ends up being a pretty convenient measurement for 5-10 gallons batches of home brew. This method is pretty wasteful unless you reuse the plastic bags, but I have yet to find a better way of storing fruit in an airtight medium. When the bags are full, place them in a stand-up or chest freezer for safe keeping. Freezing is an important step in this method as it works to break the fruit cell walls down. Citrus skin is very tough and is naturally resistant to the elements so weakening it is necessary to get saturation when added to beer.

I typically freeze my kumquats for 1-2 weeks before use. Now that they are frozen, they can be stored this way until you need them.  Freezing fruit is common practice in sour beer brewing so don’t be afraid to do it with berries and other fruit as well.

Add to Beer

Kumquats_KWBarnes_13Whole frozen kumquats can be added to beer at the tail end of the boil or during secondary. Because the fruit has been frozen, it will be brittle, and as soon as the temperature is raised the cells will burst forth with citrus oil. It is for this reason that you’ll want to add these directly to your beer frozen, not thawed. If thawed prior to use you’ll risk losing some truly amazing volatile oils and flavors.

So why don’t you slice, zest, peel, or blend them up prior to use? First off, it’s a pain in the ass. Second, if you blend them up you’ll be blending up the seeds, releasing pectin, and probably some unwanted flavors. Juicing them will add tartness to your finished product, but the contact time with the sweet citrus peel will be absent. De-seeding is an absolute waste of time and you’ll be exposing the inside of the fruit to air for prolonged periods of time. This is also the most sanitary way to add kumquats to beer. Because the fruit peel is strong and intact during the cleaning process, you’ll be able to fully (or close to it) sanitize them provided the inner fruit is not exposed. It’s not aseptic, but if it’s good enough for commercial beer production, it’s good enough for home brew.

I find that long-term exposure to whole frozen kumquats produces the best result. They hold their shape, but fear not, beer has no problem penetrating through a frozen kumquat peel (just like making jungle juice). It makes clean-up easier and you can even eat these beer filled wonders when you’re done with them. If you’re bent on getting every last drop of beer, you can press the kumquats after fermentation, but be warned, they disintegrate fast, which is yet another sign that this method works well.

I love these little citruses and I hope, by using this method, you’ll find a new interest in them as well. If you have any comments or alternate methods, I would love to hear about them.  Cheers!



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  1. Great post! I want to use them but it’s too expensive up in Canada

  2. Brett:

    Hi Kip, Great write up. How long are you typically leaving the beer on the fruit for? Would 2# be sufficient per 5gal, I don’t want to over do it. Thanks!

    • Kip:

      Hi Brett, Thanks! Depending on the style the contact time really varies. For whole frozen kumquats, I’ve been leaving it on the beer for about 14 days. Dosing this way really depends on how intense you want the fruit. For our commercial ratio, it would equate to about 1 lb for 5 gallons, but I’ve done as much as 1 lb per gallon before. The result I got from 5 lbs in 10 gallons of beer was pretty nice. You’ll need to taste the fruit to figure out what sort of character it’ll add to the beer. I have literally 100’s of pounds of kumquats and each tree produces significantly different flavors. You may decide you want to add more or less if the fruit is particularly tart, bitter, or sweet. Does that help? The batch that I really liked was 10 gallons of saison (taken through 10 days primary fermentation), 5 lbs of kumquats, and 14 days of contact time at 60-65 degrees.

      • Sean:

        Great write up Kip! Thank you for all of this useful information.

        What are your thoughts with 5 lbs in the boil? Do you feel 14 days in secondary is the best method? I’m brewing 10 gals, but I’d like to split the batch up after primary is done, and pitching brett onto 5 gals. I won’t have an opportunity to add kumquats this way, seeing as it’ll be aging for 3 months.


        • Kip:

          Hi Sean. Thanks! I’ve definitely added kumquats to the boil and that method works great. The main difference will be the pectin and a more cooked citrus flavor. I really depends on what you are looking for in the final product. If you end up boiling 5 lbs of kumquats you’ll end up with a very cloudy beer that you wont be able to clear easily, but that may not be an issue. You also get a more preserved citrus, like fruit leather/caramelized citrus sort of flavor.

          That being said, if you do split the batch, there is no reason you can’t add kumquats to secondary. Citrus will probably make the brett work harder, but I’ve done this and ended up with a great beer. I threw about 5lbs of kumquats into a carboy with a lambic and let it sit for about 6 months, the end result was great.

          I think you really just have to figure out what sort of flavors you are looking for and if you do add them to secondary you’ll want to clean the kumquats extra well. Fresh fruit to secondary will give you a brighter and more intense flavor in my opinion and I like this option when it comes to Saisons and wild/sour beers.



          • Excellent! Thank you for the response. I’m considering splitting the 5lb batch of kumquats into two, 5 gal batches. Will 2.5pound per 5 gals be enough to add some of that citrus flavor to the beer?

          • Kip:

            Sorry for the delay in answering this. 2.5 pounds would be plenty. But again it really depends on how much you want to punch the drinker in the face with the fruit flavor. I’ve also found a pretty vast difference in potency of flavor coming from different fruit trees. Some trees have very mild fruit and some are intensely sweet or intensely sour. I would definitely eat a few kumquats off of different parts of the tree to get a general sense of what the fruit is like…then figure out how extreme you want the taste. i’ve brewed 10 gallon batches with 1lb of kumquats and others that I use 5-10 lbs. One caution is that citrus oil tends to affect head retention. Using more kumquats may give your beer a fleeting head.

  3. This is awesome… I am trying to grow some kumquat .. so far… only a little seedling. lol.

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