==Forms of Fruit==
===General Forms of Fruit===
Fruit is available to the brewer in multiple different forms.
* '''Whole or sliced fresh''' - Use a CO2-purged keg or minimize headspace in a carboy. Mold and acetic acid bacteria can grow on the skins of floating fruit <ref name="kohlmorgen"></ref>. ''Brettanomyces'' can also produce acetic acid in the presence of O2, and it is possible that this is the source of acetic acid sometimes found in beers with floating fruit rather than acetic acid bacteria. Some brewers like to swirl the fermenter every few days or to keep the alcohol in contact with the fruit, though some others report no ill effects from not swirling the fermenter (and this is impractical in commercial settings). If using a barrel or larger fermenter, you may try using a punch-down technique. If punching down the fruit, purge the headspace of the vessel with CO2 to avoid oxygen exposure to the beer. Allow the fruit to get fully or possibly even over-ripe (not rotten) for best flavor. Whole fruit may take longer to ferment but it also can give the most complexity <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1123884634306416/?comment_id=1123893237638889&offset=0&total_comments=9&comment_tracking=%7B%22tn%22%3A%22R0%22%7D Thoughts from Raf Soef on using whole fruit in a MTF thread]</ref>
* '''Zest''' - the zest (outer layer) of citrus fruit is often used in beer. It is often added to the end of the boil, but tinctures can also be made and added after or during fermentation, or citrus zest can be added to the beer directly.
* '''Frozen''' - Many [https://www.facebook.com/groups/MilkTheFunk/permalink/2078296595531877/ exotic fruits] are available at world markets in frozen format.
* ===Prefermenting, Brining, and Other Pre-processing Methods===:''Editor's note: This section was written by Matt Firetto and reviewed by Jeffrey Airman.''====Overview of Fermented Fruits====Performing a fermentation before introducing fruit to a beer can help provide more complex fruit flavors, and in many cases create new savory flavors not found in the raw fruit. Some of the most common fruit based fermented products are simple salt based "Lacto-fermentations" (pickling). These fermentations utilize naturally occurring ''Lactobacillus''and other microbes on the fruits skin to ferment the fruit, while the salt helps to reduce yeast activity and other harmful spoiling microbes. A common method calls for simply salting fruit at a rate of 2% by weight (20 grams salt for 1kg fruit) <ref>[https://www.splendidtable.org/recipes/lacto-blueberries René Redzepi and David Zilber. "Lacto Blueberries". The Splendid Table blog. Excerpted from The Noma Guide to Fermentation. 2018. Retrieved 05/18/2019.]</ref>. General best practices for food based "Lacto-fermentations" should be followed such as: even salt distribution, minimizing oxygen contact with fruit, and fermentation temperatures at or slightly above room temperature. If the fruit does not release water to create a natural brine, a brine solution can be made to help ensure a more even distribution of salt and create a lack of oxygen in the fermentation vessel. Common fruits utilized for "Lacto-fermentations" include lemons, blueberries, cherries, pineapple, gooseberries, plums etc. Other Processingspices or herbs can also be used to add additional flavors during fermentation. Similar to a brine, another method documented in "The Noma Guide to Fermentation" utilizes a honey/water/salt solution with fruit to produce a ''Lactobacillus'' fermented syrup flavored with fruit and/or spices <ref>[https://www.workman.com/products/the-noma-guide-to- fermentation "The Noma Guide to Fermentation". René Redzepi and David Zilber. Workman Publishing. October 16th, 2018.]</ref>. ====Resources For Fermented Fruits ====[https://www.workman.com/products/the-noma-guide-to-fermentation "The Noma Guide to Fermentation" by René Redzepi and David Zilber] includes detailed information on how to perform "Lacto-fermentations" and other fruit/vegetable based ferments. This book provides a general framework and guidelines that can work for a variety of fruits, with a focus on creating new flavors and experimenting rather than an exhaustive list of recipes. [https://www.wildfermentation.com/the-art-of-fermentation/ Sandor Katz] has also written several books on home fermentation that provide detailed information on a wide variety of fermented products including fermented fruits. [https://www.facebook.com/groups/143258836399455/ The Ferment All Things Facebook group] includes many posts of various fermented fruits and vegetables, and is a good source for ideas and guidance. ====Concerns When Utilizing Pre-fermented Fruits====High salt content is one of the main concerns when utilizing "Lacto-fermented" fruit products, especially when used at the higher end of recommended fruiting rates. Some fermented fruits (ex Moroccan style preserved lemons) can have a significant amount of residual salt in the final product. Excess salt can be saltedremoved by simply washing off excess salt <ref name="Airman_MeadHouse">[http://www.themeadhouse.com/podcast/mead-house-episode-109/ Jeffrey Airman. The Mead House Episode 109. Retrieved 05/18/2019.]</ref>, or by soaking the fruit for a short time in clean water. Fermented fruit products can have a significantly different flavor profile compared to raw fruit, so fruiting levels may need to be adjusted depending on the intensity of the fermentedfruit product and base beer.Due to the wild and spontaneous nature of these types of ferments, smokedvarious wild yeast and bacteria are typically present. Depending on a beer's residual sugars, cookedthese microbes may or may not be a concern. If this is a concern, etcfermented fruit can be heat pasteurized or frozen to help reduce the potential for these microbes to alter the beer <ref name="Airman_MeadHouse" />. that If fermented fruits are introduced early in a beer fermentation, the overall yeast/bacteria character of the beer fermentation can bring out specific be impacted. ====Other Alternative Processing and Fermentation Methods====Caramelization of fruit juices, smoking, spontaneous or additional characteristics in some kombucha based pre-fermentation, and other culinary inspired methods can also be used to help transform fruit. This Paradox Beer Co's Pineapple Upside down sour was created using a candi syrup created from pineapple juice raised to a PH of around 6 with baking soda to increase the maillard effect and provide a more intense long lasting caramelized flavor 2 ====Related Milk the Funk Facebook Group Posts and Other Links====* [https://www.facebook.com/groups/MilkTheFunk/permalink/2410834822278051/ MTF thread] started by Jeffrey Jeffery Airman of Paradox Brewing briefly discusses brewing discussed some of these approachesmethods and comments include ideas and experience from others.]* [https://www.facebook.com/groups/MilkTheFunk/permalink/2644816718879859/ Brian Detweiler posted about "Lacto-fermented" blueberries and others provide examples of fermented fruits used in beers.]* [https://www.facebook.com/groups/MilkTheFunk/permalink/1335647439796800/ DeWayne Schaaf posted about Umezuke (Japanese salt preserved plums).]* [https://docs.google.com/spreadsheets/d/1yQ9m6-JUCwzkeDjd6bPyKU9B4Lc2M6acfGxxLyCA9OI/edit?usp=sharing Examples of fermented fruits in beers (Google Doc).]
==Fruit varieties and usage suggestions==