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  • Scaling up liquid soap production - do I really need a machine?

    Posted by stephanm on February 11, 2016 at 7:35 pm

    Hi! Newbie here.

    We have been running a very amateur liquid soap making operation for a year. As in - fully made and mixed by hand and sold at farmers markets/to friends. The consistency of our soap is not very even, and in general it doesn’t seem as ‘polished’ as a mass market body wash. That’s always been the charm of super hand-made farmers market stuff!

    We’re looking to scale up operations and begin doing e-commerce and selling into other businesses. We have to start making a more professional products.
    Our soap is of the ‘all natural’ type (that’s the branding), and the ingredients are roughly as follows (this may not be important to the question but I’m including it for full info):
    Saponified oils of Coconut and Olive, Jojoba Oil, Guar Gum, Glycerin Extract, Aloe Vera, and a few different essential oils.

    The question:
    Should we invest in a mixer? Is such a machine really something that any respectable small-to-medium business uses during the manufacturing of liquid soap?

    We use a little stick blender to make the ‘saponified’ ingredients, sure, but after that, when all the ingredients are combined to make the finished product, we’ve never had a mixer to really help things. Some of these ‘high shear’ mixers I’ve been reading about might help with consistency, reduce opaqueness of the final product (clear is better, but we never achieve it), etc. Perhaps there are many benefits that I’m unaware of.

    David08848 replied 6 years, 1 month ago 8 Members · 43 Replies
  • 43 Replies
  • Bobzchemist

    February 11, 2016 at 8:49 pm

    Scale-up can be tricky - and expensive.

    The most important question is… how big are your current batches? Also, can you share your current production procedure?
    The next biggest question is… how confident you are in future growth? The more confident you are, the more likely it will be that you can ultimately save money by skipping an intermediate step or two.
    As an example, if you wanted to move up a step from where I think you are, you would buy a big commercial stick blender, a heavy-duty small overhead mixer, and some large stainless steel cooking pots with lids. Total cost probably between 2-4 grand.
    The next step up would be to buy a pilot-sized homogenizing mixer, a pilot-sized overhead mixer, and one or two medium-sized soap mixing tanks. Total cost about 8-10 grand for decent used equipment, probably closer to $20,000 for all new.
    My point is that you could skip the first step, and go right to the second, if you were convinced that your business would grow to need that capacity. Doing so would save you the $2-4,000 you would have spent - but you are taking more of a financial risk.
  • OldPerry

    February 11, 2016 at 9:48 pm

    Or you could hire a contract manufacturer and spend your time and money focused on marketing your brand.

  • stephanm

    February 11, 2016 at 11:02 pm

    @Perry: for various reasons (amongst them being that one of our founding members is really passionate about making everything herself) we have decided to keep production in-house.

    @Bobzchemist: I’ve browsed a few topics on this site and indeed you appear to be the master wizard here! Thanks for the response!

    Our current batches are not big. We’re talking less than 10 litres. One of our directors is a veteran investor, and I myself have raised funds for other companies in another sector - so we have the means and desire to invest some money into scaling up. 

    Having said that - I’m interested in your first idea. The one that involves scaling up ‘to the next step’. I think we’re going to enter a phase where we spend 6 months giving out samples, marketing into private institutions through various channels we have, etc. I think we can invest a few thousand on equipment during this phase, and leave the larger scale investments (the $20k you mentioned) until later.
    I’ll get back to you ASAP with the current production procedure. My partner will have to explain it to me!

    Regarding the big commercial stick blender, overhead mixer, pots and lids - and I realize I’m asking a bit much here - would you happen to have a specific recommendation for each? As in, a link to a product you think is most suitable?

    Thanks for your time-
  • belassi

    February 11, 2016 at 11:31 pm

    There are good reasons that synthetic liquid soap dominates the market. Are you sure that your product would be able to compete in the wider world? I already made that decision, and it was to go synthetic.

  • stephanm

    February 12, 2016 at 12:39 am


    These steps come after we produce the saponified oils of coconut and olive.

    We have jugs of each of these 2 oils; pre-produced, since it takes about 5 hours to finish the saponification procedure.

    If the saponification procedure is what you’d like to know more about, please let me know. It involves the big pot, mixing, a stove, and a stick blender at times, etc., as you’d expect to find in a home ‘liquid body wash’ making hobby.

    So, starting with our 2 saponified oils and the rest of the ingredeints:

    1) Mix xanthan gum into glycerine (by hand, at room temperature..) (switching to guar gum)
    2) Mix saponified oils of coconut and olive oil with (golden) jojoba oil and aloe vera (by hand, at room temperature)
    3) Slowly mix #1 and #2 together. (by hand, at room temperature)
    4) Add essential oils to the mix
    5) Mix everything together (by hand..)

    There’s no heat involved (except for during the production of the saponified oils of coconut and olive), and we haven’t used any machines except for a stick blender during the saponification of the base 2 ingredients.

    Again - this has all been farmers market stuff; of wildly inconsistent texture and clearly inferior homogenization.

    I guess what I’m really trying to learn is what kind of machinery should we be using during the above steps.

    As an aside, our company’s historial sales have been essential oils, essential oil blends, essential oil ‘roller ball’ sticks, etc. This body wash product is aiming to be a new line, and will fit into the ‘natural and infused with essential oils’ branding. 

    @Belassi: we’re OK to live in the niche world. As an example of a niche body wash that lives in the world of “natural ingredients”, there’s Defense Soap, amongst others: http://www.defensesoap.com/defense-soap-shower-gel.html

  • Mike_M

    February 12, 2016 at 2:10 pm

    Hallstar has an entire line of olive oil surfactants that are really nice and have some favorable characteristics. This may be something of interest to you. This could save you some time with saponification and also lead to a bit more uniform end product.

    Good luck with your expansion!

  • Bobzchemist

    February 12, 2016 at 3:21 pm

    I’ve mentioned some of this stuff before on here, but probably not all in the same place, so here goes:

    For a “stick blender”, what you actually need is a “Commercial Immersion Blender”. Without knowing the size of your batches, I can’t suggest a size, but Waring has a good reputation for durability:

    For a stainless steel crockpot, something like this one:

    For an overhead stirrer, and for a lot of pilot/small-scale production equipment, look here:
    or here:

  • stephanm

    February 12, 2016 at 7:57 pm

    @Bobzchemist: thanks for the links! Indeed I’ve seen you recommend that “commercial immersion blender” before in another thread. 

    To be clear: this blender would be used during the saponification stage (where we’re mixing water/olive (or coconut) oil/potassium hydroxide over a double boiler to create the ‘paste’, etc)?
  • Bobzchemist

    February 12, 2016 at 8:39 pm

    Yes,it would. You need a slow stirring mixer for your dilution step.

    But…double boilers are intrinsically unsafe, because of potential steam/hot water burns. There are safer ways of heating batches.
  • stephanm

    February 12, 2016 at 10:28 pm

    @Bobzchemist: the partner who makes the soap learned the double boiling method at a local ‘soap making school’. Pot inside an even larger pot which is filled with boiling water. This is the basis for the saponification stage (which takes 3+ hours of heating, occasionally mixing, etc., until gel!)

    I think you’re telling me that this method is very… ‘arts and crafts’ style, and not something that might scale?
    What would you recommend as a safer way of heating batches?
    Also, regarding a slow stirring mixer - I suppose this would be used for everything post-saponification stage. A high speed immersion blender has no more use post-saponification, correct?
  • Bobzchemist

    February 12, 2016 at 11:06 pm

    There’s absolutely nothing wrong with using hot water or steam to heat a kettle, and it scales very well - it’s the double boiler part that’s dangerous. Simply put, you have to make very sure that the hot water/steam is safely contained, and has no chance of escaping to burn someone - that’s impossible to do with a double boiler setup.

    Kettles can be heated in any number of ways - where the heat comes from really makes no difference to the batch as long as you can avoid hot spots.

    Something like this, for example, can accept hot water or steam, and do it safely:

    Something like this, on the other hand, has heating elements permanently submerged in water - it’s a double boiler, but with no chance for the water to get out:
  • stephanm

    February 13, 2016 at 12:30 am

    @Bobzchemist: great advice, thanks. Understood. So - we ought to have a much safer and controlled way of ‘double boiling’ during our saponification stage. The products you just shared look great, if not a bit expensive - but totally opens up my mind re: what I should be looking into!

    I’m curious - you mention that there’s ‘nothing wrong’ with double boiling to make our base soap gel; does this imply that there are perhaps other methods that I might explore?

    Our base soap gel is simply water + potassium hydroxide + olive/coconut oil.

    And thanks again!

  • belassi

    February 13, 2016 at 3:41 am

    Other methods:

    Purchase potassium cocoate 50% and potassium oleate, blend 25/75, dilute to required concentration, add any active ingredients e.g. glycerin, thicken with salt.
  • stephanm

    February 13, 2016 at 8:11 am

    Are there any of these lovely ‘electric all-in-one double boiler’ machines that are less than $4-5k? They look fantastic but are a bit out of our budget.. perhaps I could find a used one up in Vancouver (Canada)..

  • David08848

    February 15, 2016 at 11:25 pm

    I have read most of your responses and the first thing I noticed was that you mentioned:

    “The consistency of our soap is not very even, and in general it doesn’t seem as ‘polished’ as a mass market body wash.”

    Perhaps you may wish to work on your formula and techniques before you try a production batch?

    Basically, my liquid soap is made by heating the oils, mixing the KOH with water in a plastic bucket until combined then adding the solution to the oils and stirring until saponified and it turns to a paste.  For me that takes about 10 minutes.  It is then covered and left overnight to make sure the saponification process is complete.  The next day the paste is weighed to determine the amount of H2O to be added, water is then heated then my thickener is added and stirred until dissolved, then the soap paste is added to the heated water and stirred then left to be dissolved by the heated water then covered. (glycerin can be added at this point if used).  Usually the by the next day the paste is totally dissolved and the fragrance can be added and it is weighed again to see if H2O needs to be added to bring it to the proper concentration reflected in the formula and it is then ready to bottle.  For this type of production a mixer is not needed.

  • belassi

    February 15, 2016 at 11:45 pm

    @David: great explanation.

  • stephanm

    February 17, 2016 at 1:04 am

    @David08848: thanks for your advice. I’ll pass that on. I was hearing that “KOH + water + oils -> paste” stage took around 3 hours, so I’m surprised to see that it only takes 10 minutes for you. Will inquire!

  • Bobzchemist

    February 17, 2016 at 1:31 am

    What size are your batches?

  • stephanm

    February 17, 2016 at 8:26 pm

    @Bobzchemist: She has historically been making around 3lbs of the saponified paste. Like.. super small batches.

    I’m very much confused about the ’10 minutes to saponify’ part. Her teacher (and all the video material) includes over 3 hours of cooking until you get the paste.

    Even looking at instructions from a local soap making shop (http://www.voyageursoapandcandle.com/How_to_Make_Natural_Liquid_Soap_s/367.htm), they say the following:

    Continue cooking the mixture for a minimum three hour period. During this time, you will note that the mixture will become translucent. After three hours turn off the heat and let the paste stand in the double boiler overnight if possible.”

    I’m really confused how some people can say 10 minutes, and others 3+ hours with the same ingredients (oil, KOH + water)..
  • belassi

    February 17, 2016 at 9:13 pm

    If you use fatty acids (e.g. oleic acid) it takes seconds rather than minutes. Three hours is ridiculous.

  • Bobzchemist

    February 17, 2016 at 9:57 pm
    OK, I think there’s some confusion over terminology, and maybe over what’s going on chemically.

    If you have everything hot enough, getting the oil/water/KOH mixture to a certain thickness (called ‘trace’) takes 10-20 minutes of high-speed mixing.

    Chemically, “trace” is the point where enough of the KOH has reacted with the oils (making soap) to both emulsify the remaining oils and thicken the batch significantly. The emulsification is stable enough that you can stop high speed mixing at this point. The remainder of the oils and KOH will now react on their own without the need for external energy.

    If you continue to heat and stir the batch, however, the soap reaction will run to completion in 3-4 hours. If you turn off the heat and mixing, the way @David08848 does, then it will take 8-10 hours, or overnight. If you’ve run the reaction to completion (all the oil has turned to soap) you really don’t need to leave it hot in the double boiler overnight - that’s just a precaution.

    So, now that I know your batch size and process, here’s what I suggest for expanding production.

    Buy this tank: $822
    This blender: $395

    This Clamp: $92

    This overhead mixer: $693
    Or possibly this whisk attachment (if your budget’s tight):  $250

    If you get the overhead mixer, you will want to cut a hole in the tank lid for it, and you may need to open up the support ring a little.

    Total cost =822+395+92+693 = $2,000 (US)

    I’d strongly suggest following David’s method - it will keep from burning out your mixer.

  • Bobzchemist

    February 17, 2016 at 10:11 pm
  • stephanm

    February 18, 2016 at 8:03 am

    @Bobzchemist: Fantastic answer! Thank you so much. You’ve completely cleared up everything, and pointed out how we may improve our process. Also, I have a good idea re: what hardware to obtain. (I’ve even found that Waring immersion blender on Craigstlist!)

    For reference - she hasn’t been using the mixer (stick blender) for the full 3 hours. Most of it is just ‘open up the lid every 30 minutes and stir by hand’.

    But now I understand why there are 2 different times as explained by the chemical process (the external energy that we added for 3 hours accelerated the process, I suppose, though it wasted a lot of time to monitor, keep boiling, etc). We can just let the chemical process run its course overnight!

    If we have any more silly questions I’ll ask in another thread. You’ve all helped me out more than enough here. Thanks from Vancouver, Canada! :)

  • mikethair

    February 20, 2016 at 10:05 am

    At Indochine Natural we have more or less evolved as you have described stephanm using a similar process of saponification…..small 10 Kg batches and now we use a 20 Gal (160 lbs) Water Jacketed Melter/Heater, and Waring 18″ Commercial Duty Power Wand as identified above by BZChemist. We have not seen the need to purchase a overhead stirrer.

    Overall, works well for us, and product demand is high. We run this machine almost every day to keep up with deman, and are probably at the point of needing to invest in a second set up.

  • stephanm

    February 22, 2016 at 7:47 am

    @mikethair: why haven’t you invested in an overhead stirrer? When you mix the saponified oil(s) with the rest of the ingredients, do you just stir everything by hand in a separate container? Or do you have that whisk attachment for the Waring Immersion Blender?

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