Clean and Sterile

One of the biggest mistakes made by first-time brewers is not cleaning every bit of requirement, or not knowing the difference between “cleaning” and “sterilizing.” Cleaning is removing unwanted particles that you can see. Funk. Gunk. Nasty bits. In contrast, sterilizing is removing the unwanted particles you can’t see. Bacteria. Mold. Food spoilage organisms, like listeria. Cleaning (sometimes called sanitizing to confuse matters further) cannot get rid of the unseen, and sterilizing alone will not get your equipment “clean” enough to guarantee that there is not something lurking under a big glob of goo that could survive a soak in iodine.

Cleanliness is essential

If you begin brewing a lot, at some point your will find yourself with used bottles. You will have friends bring them to you in hopes of scoring some cider, or you will run short of flip tops and have to head down the recycle center in search of more containers for your 5-gallon batch! (Remember not to get any screw top [twist-off] bottles, the threads will not work with your capper, and the neck is thinner glass so it can break) Even if your equipment is all “brand new” it can have oil from fingers or residue from the factory. You need to get in the habit of washing everything, every time. If you don’t, you invite trouble. Trouble is expensive, and it tastes like apple cider vinegar!


  1. Step one: Give it a soak. The bathtub comes in handy for this. You want to soak your bottles for at least overnight to get rid of big goo. I find that using an oxidizer like “PBW” by Five Star really helps to bubble away the funk. Some folks use bleach, but this is a good way to ruin clothes and towels. Bleach will not kill near what PBW or iodine will, and well, it tastes like bleach. If you are just cleaning bottles that are new, or that you cleaned properly last time, give it a good 15+ minute soak. I leave my siphon tube soaking for a good hour to let the oxidizer get all the way in the tube with its bubble action.
  2. Step Two: Remove any labels. Guinness bottles are wonderful because the label is held on with a water soluble glue. Sliiiiides right off with a little soak. (I am of course referring to the Guinness bottles with the tan paper labels, not the shrink-wrapped black ones with the carb tab inside) Some bottles have labels held on with solvent based, NASA engineered, whale-snot–and you can spend an hour working on removing a single label. The day after Saint Patrick’s Day is a wonderful time to go bottle collecting at the recycle center. Guinness bottles galore!
  3. Step Three: Give it a scrub. Even if you don’t see any cling-ons, the inside of a bottle has lots of little crannies for stuff to hide. You are going to need a good Bottle Brush (like photo on left).
  4. Step Four: Rinse it well. Who wants a bunch of oxidizer or soap in their brew? Not you.

And now that everything is washed up, let’s move on the getting things sterile!

Now let’s make it sterile.

Clean vs. sterile is a matter of how many organisms are left alive on a suffice after you treat it. Soaking a glass (or plastic or rubber) surface in a solution of iodine will do the trick to remove almost all of the microorganisms. It will also stain everything (including you) yellow-brown. Bleach will work as a sterilizer too. However, bleach will destroy plastic and rubber. I don’t use iodine or bleach because it is very easy to end up with an off-taste in your brew, but also because it will stain and destroy plastic equipment.

My top recommendation for a sterilizing solution is StarSan because it is effective, does not add an odor, and it is inexpensive ($11 for 8oz). This is an acid based sanitizer that you mix 1oz to 5 gallons of water–and the mix will last 3-4 weeks so you can reuse it. If you mix the ratio correctly, it will leave no taste, and need no rinse. There is a handy mix-measure top in the cap, so all you have to do is add the right amount of water. Over time, StarSan it breaks down to a simple sugar that is actually food for the yeast, so no off flavors! If you get out on many brew blogs, you will see Star San as the sterilizer of choice. Click here to buy StarSan on with free shipping Here is how it works:

  1. Step one: Mix up a batch of sanitizing solution using tap water and 1oz of Star San per 5 gallons. The squeezy measuring cap makes this foolproof. If you add too much, the taste may linger, and your brew will taste “off.” Add too little, and well, you will not have a sterilizing solution because it will be too weak. If you are mixing up a soak in the sink, or in a bowl, measure your water out by filling up your 1-gallon jugs and pour them in the sink or bowl. Measuring your water is just as important as measuring your Star San. Duh.
  2. Step Two: Shake off any extra water left from cleaning your bottles (or equipment) in the sanitizer. I lay my bottles on their sides for a few min and then shake drain.
  3. Step Three: Give everything a soak in the sanitizer solution for AT LEAST 2 minutes. You can leave the glass in the solution longer, but don’t rush this. If you are going to be brewing in a 5-6 gallon carboy, fill that pup up and let it sit 15 minutes. When you pour the solution out, you can catch it and use it to sanitize everything else for the next 4-weeks.
  4. Step Four: DON’T RINSE, or dry with a towel! What would be the point of washing off your sterile bottles with nasty tap water or a dirty old towel? All you want to do let the equipment air dry and shake off the excess water as it dries. Again, I tilt the bottles/carboys on their sides and let the solution drain to one side, rest, and then pour off. If you need to store your bottles for a bit, a freshly cycled dishwasher is fairly sterile¬†and makes a good staging area. If you are not using your carboy right away, cap it with a sterilized bung (cork).
  5. There have been a few questions come in about the Star San making big bubbles in the bottles. First, make sure you are adding the right ratio – 1oz to FIVE US gallons of water. When you pour out the Star-San, do it slowly and don’t let the solution-water “glug-glug” when you pour. If the bubbles are persistent, you can choose to rinse the bottles/carboy out with a little bottled water or freshly boiled water. When I make wine, I usually lightly swish-rinse the bottles to make sure the StarSan won’t make suds in my wine (been there).

So just remember that everything that is going to come in contact with your brew is going to need to be washed and sterilized. Measuring cups, measuring spoons, funnels, hoses, your hands… everything. That happy little bacteria that can spoil your brew could come from anywhere. Scary? Yes, but you can do this. Just be careful.

Got the gist? Let’s move on to Selecting the Fruit and Yeast.

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