The brewing process for hard seltzer is super quick and and easy.  I've listed my process below along with a few important things to consider before brewing your first batch.

Water:  There is quite a bit of discussion on water for hard seltzer, mainly around the clarity of the finished product.  I use tap water for mine since I don't care if it's a little cloudy or not.  Mine does usually clear out almost completely after sitting in the keezer for a week or two, but I don't stress about it.  If you choose to use RO or Distilled water, you may need to add some brewing salts back in, depending on how much you get into water chemistry.

Yeast Nutrient:  Since you are only fermenting sugar and water, the yeast will want/need a little help to get going.  I'm lazy, so I only do one yeast nutrient addition in the kettle.  Others have had good luck with staggered nutrient additions, which have really caught on in the mead world over the last few years.  That requires buying different types of nutrients and adding them over the course of a few days when fermentation is first starting off.  Both methods will result in a good seltzer, so do some experimenting and see what works for you.

Flavoring:  There are several different flavoring options for hard seltzer.  I've experimented with the standard beer fruit flavorings (usually made by Brewers Best (BB)) as well some Amoretti Craft Puree, which adds a really fresh and bright fruit flavor.  Both have their benefits and drawbacks.  The BB flavorings are relatively inexpensive, but some are better than others.  I find the Cherry to be very artificial tasting, and the Peach tastes more like canned peaches rather than fresh.  The Amoretti has really great and fresh fruit flavor, but the cost is around 4-5 times that of the BB option.  I have been experimenting with the BB flavors at kegging, and then adding a splash of the Amoretti Craft Puree to each glass if I think the batch needs more flavor.  As I dial in what BB extracts I like and in what volume and combination, I will probably use less of the Amoretti, but it all depends on what I'm looking for.  I would suggest trying both and seeing what your preference is, or go with a combination as I have been doing.

Yeast:  I used a pack of 71-B yeast on my first batch of MikeClaw since I already had that in the fridge.  The end product seemed to have a little more frutiy esters than what I wanted, but at least I proved the process worked.  After that, I've been using Lavalin EC-1118 champagne yeast, and I'm finding that to be a bit more neutral.  There is still some fruity pear esters in the aroma, but the flavor is really clean.  I find that the light esters compliment the post-fermentation fruit flavors, so it's not a big deal.  I've seen other recipes that call for US-05 or another neutral ale yeast, but I haven't tried that yet.  Wine yeast just seems like the right choice for this beverage.

Ingredients:

• 4lb Table Sugar

• 1 TB Yeast Nutrient

• 1-2 packs EC-1118 yeast

• 1-2 TB Lemon Juice (optional)

Brewing Process:

1. Bring 1-2 gallons of water to a boil along with the 4lbs of table sugar.  Make sure to stir the pot frequently until the sugar is totally dissolved.  Alternatively, you could bring just the water to a boil and add the sugar off heat, stir to mix, and add it back to the heat.

2. Boil for 5 minutes and turn off the heat.

3. Add 1 TB Yeast Nutrient (and lemon juice if you're using) and stir to combine.

4. Chill in a water bath or other chilling method until the temp is around 80-85 degrees.

5. Add the chilled sugar water to your sanitized fermenter and top up to 5 gallons with cold tap water or RO/Distilled.

6. Sprinkle on yeast, attach lid & airlock, and wait.  Fermentation seems to take a little longer with wine yeast, so give it a couple weeks before taking a gravity reading.

Kegging:

This is where I will add the Brewers Best flavoring to the keg and rack the seltzer on top of the flavoring to mix.  I've found that 4-6 oz of BB extract is about right for me, depending on the flavor(s) being used.  This is where you can experiment with blending different flavors and amounts to see what works best for you.  I would start with less flavoring than you think, then rack the seltzer onto the flavor, and try it again before you're done.  For carbonation, I just use the standard process, pressure, and temp as with my beer.  I find that the carbonation isn't quite as high as commercial brands, but that's not necessarily a bad thing, since those tend to make me burp a ton.  If you have a dual-pressure regulator, you can try a higher pressure to see what you prefer.

Recipes:

Here are a few links to the Hard Seltzers I've made so far.  I'll keep adding more as I go along on my Brew Log page, so check that out for updated recipes, processes, and ideas.

• Hard Seltzer (Multi-Berry)

• Hard Seltzer (Multi-Berry2)

• Hard Seltzer (Blackberry)

• Hard Seltzer (Mango)

Future Seltzer Ideas: 

• Double Batch & Dilute:  After talking with some pro brewers and fellow homebrewers that are making Hard Seltzer, they seem to be brewing higher gravity/double batches of seltzer and then diluting them with water post-fermentation.  I like this idea for a couple reasons.  First being that you can brew two (or more) batches of seltzer using only one fermenter, as well as the time savings.  The second would be potentially reducing the amount of esters that I've noticed after fermentation completes. If I brew a double batch and then dilute with water, I would assume the overall yeast character should be diluted as well and result in a more clean tasting alcohol base for the fruit.  I'll be giving this a try on my next batch to see how it comes out.  As part of that experiment, I will also be using tap water to dilute one half, and distilled on the other to see if I notice any differences.

• Different Fruit Flavorings:  A few of our homebrew club members have tried what appear to be vaping flavorings on both their beers and seltzers, and have had good luck with the Wizard Labs brand.  One thing they all mentioned is that these flavorings are VERY CONCENTRATED, and only require a few drops for a whole 5-gallon batch.  This kind of scares me a bit, but I may need to order a few and try them out.  The prices seems very reasonable for how much flavor they're supposed to add.

• https://byo.com/article/hard-seltzer-made-easy/

• https://brewtogether.com/2019/10/20/homebrewing-hard-seltzer/

• https://brewchatter.com/blogs/brewchatter-homebrewing-blog/the-ultimate-guide-to-homebrewing-hard-seltzer

Amoretti Craft Puree - Use to flavor the seltzer per glass or the whole batch:

• https://amoretti.com/collections/craft-purees