The short answer is no, they are not. To determine if HDPE plastic is permeable there are two things to consider; the thickness of the plastic and pressure. The outside air pressure is not enough pressure for air to pass through the walls of the tank to the inside. From the inside, one could create enough pressure. However, the tank would probably burst. A thin walled tank may breathe like a wood cask. Since our tanks are a full 5/16 of an inch in thickness, this doesn’t happen. At this thickness they will not breathe. Permeability is not a risk with Minibrew tanks and fermenters. This information comes from the plastic manufacturer.

Of course, everything scratches…. including stainless steel. Our HDPE has a thin layer of plastic that can be penetrated with a sharp knife. If this happens to your tank the problem can be easily solved. You can use a dull knife to reduce the sides of the scratch. You can also use a small propane torch and slowly brush the flame over the scratch. The fuzzy hairs will burn off and the plastic will melt and fill the void. Just be careful not to burn the plastic. The other option is to ignore it and definitely sterilize with very hot water (180 degrees) the next time you brew. Leave those expensive stainless steel spoons to the other guys. Always use plastic or wooden implements when stirring your fermenter or mash tun. There is no reason to scratch food grade HDPE plastic. Teflon frying pan coating has been around for a long time. The secret is the same for our tanks. Use a wooden or plastic stirring implement and a Teflon scouring pad. This thin layer is much like the layer on stainless steel. However, the healing process on stainless steel is more complicated and is a process of oxidation. When the outside layer of stainless steel is penetrated your tank may rust. You can scratch stainless steel if one is not careful. I bet the old brewer’s years ago, had the same problem with copper.

The answer is yes! The plastic used for our Minibrew tanks is certified by the FDA as food grade. If HDPE plastic was not pure hospitals, researcher laboratories and everyone else that needs a sterile environment would not choose HDPE.

Our tanks are easy to clean and sterilize. All popular cleaning and sterilizing agents can be used on our plastic fermenters. They will not harm the inert plastic material. Another method I use is hot water heated to 180 degrees. The heat will sink into the plastic and all parts, killing any bacteria. This procedure also works great with stainless. I can’t mention this enough. Please use only Teflon scouring pads when cleaning your fermenter.