Changes

Spontaneous fermentation of apple juice to cider is very easy and can be done without any more effort than buying fresh -pressed, unpasteurized, and untreated (raw) apple juice and then forgetting about it for a few weeks or even months. While not available everywhere, if you live in a region with apple orchards it is very easy to find in the fall. Usually sold directly by the orchards, or available at a cider mill, the fresh -pressed juice will already contain all the microorganisms needed to ferment out the sugars.

In the US your fresh -pressed juice will most likely come in a plastic milk jug style container. You have two options to ferment this juice:

# At room temperature - this would proceed much like any normal fermentation, and due to the unknown nature of the microbes contained within, it is likely to really dry out.

The cold fermentation option has some pitfalls, however, so your results may vary. Much like a lager, it is possible that you might need a diacetyl rest, requiring you to warm the cider up for a short period of time. This can kick off fermentation by microorganisms that were previously dormant, which is likely desired to reduce the diacetyl content anyway. The other major issue faced by cold fermented ciders is sulfur (H₂S) production. Due to the colder temperatures, the sulfur will off -gas less, again requiring warming of the cider to encourage off -gassing. If the cider tastes good otherwise, further fermentation can be halted with the use of sulfites. Adding sulfites (SO²) will also reduce the (H₂S) sulfur (see [https://brocku.ca/ccovi/wp-content/uploads/sites/125/Karl-Kaiser-Controlling-reductive-red-wine-aroma-2010-.pdf "Controlling Reductive Wine Aromas" by Dr. Karl J. Kaiser]). A study by Wicklund et al. (2020) compared several variables of 2 spontaneously fermented ciders and 6 ciders fermented with Mangrove Jack's M02 (''S. bayanus''). As far as the spontaneously fermented ciders versus the ciders that were fermented with the M02 yeast, the difference in volatile esters was insignificant. However, one of the spontaneously fermented ciders scored higher in fruitiness, complexity, and aftertaste than all of the other ciders except one M02-pitched cider that was dry-hopped with Amarillo hops. The spontaneously fermented ciders also had less succinic acid than the M02-fermented ciders. The greatest differences between the ciders ass far as esters go was determined by the different blends of different varieties of cider apples, with the Gravenstein and Summerred varieties scoring highest for fruitiness and complexity <ref>[https://www.iseki-food-ejournal.com/ojs/index.php/e-journal/article/view/713 Various factors affect product properties in apple cider production. Trude Wicklund, Elizabeth R. Skottheim, Siv F. Remberg. 2020. DOI: https://doi.org/10.7455/ijfs/9.SI.2020.a7.]</ref>.