Using leftover olive oil to make soap

This weekend we made our first attempt at making homemade soap. It was pretty straightforward and a lot easier than we had anticipated. There was some leftover olive oil from 2011 in the bottom of the stainless steel containers we use to keep it. We needed to remove it to refill them with the new 2013 olive oil. The leftover olive oil had gotten cloudy and thick and although we didn't want to use for cooking we couldn't just throw it away.

So we looked up some online recipes and found a great DIY video of how to make olive oil soap.

We followed the recipe adjusting the dosages and confirmed the lye proportions using an online lye calculator (inputing 0% superfat and 0% lye discount). The only ingredients you really need to make oilve oil soap are lye and olive oil. Lye is produced by mixing together granulated sodium hydroxide (also known as caustic soda - available in any hardware store) and water and is very corrosive. You need to wear protective gear (gloves and protective glasses) to prevent chemical burns from splashes.

We had 1773g olive oil, so according to our calculations we needed 237g caustic soda and 663g water to make the lye. We weighted the olive oil first to be able to make just the lye we needed - you don't want to store leftover lye...

We used only plastic and silicone containers and tools because lye can damage glass and wood and react vigorously with some metals (like aluminium) to produce highly flammable hydrogen gas.

Then we weighed the caustic soda and water and added the caustic soda to the water (never add water to caustic soda!).

Mixed it well until it became fully dissolved and transparent. Making lye is an exothermic reaction and it really heats up! We did it outdoors because of the fumes that are released during the dissolution.

Gently poured the lye into the olive oil.

Gave it a mix with a plastic spoon.

And then used a hand blender to speed up the process of getting the soap to trace. Trace is a sign of emulsification, meaning that the oil and water are completely mixed together and are not going to separate again. It is called trace because when you drizzle a little of the mixture back into the container, you see a little ridge or trace of it left behind that takes a few seconds to disappear. Before hand blenders were available, it took 3-4 hours to thoroughly mix the ingredients; now it takes 2-3 minutes. We used an old blender since we wouldn't trust it inside a soup pan again.

We replaced the essential oils and dye with some fresh lemon verbena (Aloysia citrodorathat we shredded into the mixture with the hand blender.

Poured the mixture into two IKEA silicone backing molds to make it easier to unmould. You can also pour it into molds that will make individual soap bars.

And finally covered the molds with a chopping board and towels to keep it warm during the saponification process. Most recipes say you can cut your soap in slices after 24 hours but we will leave it a few days longer. It will then need to cure for about four weeks to be ready to use. We'll update this post after our first bath with homemade soap! Let's hope it's as good as the 8$ version.

Making our own olive oil

Our location isn't ideal for olives. We usually only have any meaningful quantity every two years. We've been trying to improve that by bringing in new olive trees of different species and watering the trees more. Two years ago we had a great harvest and made enough olive oil to last almost two full years. Last year was an off year and this time we've had a decent but not great harvest.

Harvesting olives is pretty simple. At the end of autumn when it gets cold and the olives are fully mature you set a tarp under the trees and wack them with a stick a few times to make the olives drop. Ideally you'd immediately make olive oil or cure them to make them edible (olives are incredibly bitter if eaten straight from the tree). Since we don't have a large quantity or the ability to harvest everything at once we first keep them outside in cold water to keep them from spoiling.

The day we had scheduled to make the olive oil we sorted through a few last olives to select a small quantity for salt processing to get cured olives. We'll detail that process in a later post.

Once we had selected everything we put them into plastic bags, roughly 30kg to a bag. We ended up having about 300kg of olives. We loaded all the bags into the newest addition to the farm, an electric utility vehicle. This made getting all the olives to the car much easier. Electric rear wheel drive works wonders for the steep paths we have at the farm. We need to write a post just about this as well, as there are plenty of pitfalls on how to choose and buy one of these.

We then loaded the olives in the car with a tarp under to try and keep it clean. All the family wanted to go and see the oil making so we ended up using two cars instead of dropping the back seats and loading it all into just one.

Once we got to the local olive oil factory we realized we were in for a wait. We had a scheduled appointment but they were running very late. After waiting for 2 hours we eventually got our turn. We unloaded the olives in the loading dock and they got transferred around the factory to the large containers at the start of the line. When it was our turn they opened our container and the olives started flowing.

The first step is to go through a washing stage. The olives are rinsed in water and then vibrated to dry them again.

Unfortunately after that step nothing is really visible any more. The factory is mostly automated. The olives are grinded into a paste and cold-pressed to separate the oil from the rest.

After running through the whole process a final tap releases the oil into a final tank from which they fill the jerrycan containers we brought. This year we produced around 28 liters of oil from the 300kg of olives. That's around half of what we got two years ago so we have to make it last longer.

At this point the olive oil is still pretty cloudy. We let it sit in the jerrycans for a while and only started using the oil when most of the solids had settled in the bottom. The oil tends to have a much stronger flavor than the store bought one. Because the olives waited for a week or two between harvest and processing the acidity levels are a bit higher than usual but not by much. It doesn't really impact the flavor.

When we have a lot we use it for cooking but since this year we don't have as much and since olive oil is very cheap in Portugal we'll probably keep this one mostly for dipping bread in and eating raw. Yum!