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Using dishwasher rinsing liquid as a defoaming agent


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After reading (with considerable interest) the thread on DIY defoamers, I'm left wondering if the rinsing aid liquid intended for dishwashers might be used to prevent excessive foaming in grain-based washes during distillation. We make and supply products for home and craft distillers, and especially our home distilling customers have apparently been experimenting with a variety of grains lately, some of which may be somewhat high in protein and other compounds promoting wort viscosity, and we've had a lot of inquiries about products to prevent "puking". The only commercial product on the market in our neck of the woods is a silicone-based defoaming agent which works well but is expensive and difficult to obtain. The combination of 1/2 tsp of olive oil and 1 drop of dishwashing liquid per liter of wash (as suggested in the above thread) works, but on a 5 gallon batch of wash you'd need quite a bit, which makes some of our customers worry about residual flavors.

The "rinse aid" liquid used in dishwashers, as I understand it, reduces the surface tension of water. Rather, it contains surfactants and uses Mangoni stress to prevent droplet formation (Wikipedia) and the latter is based on surface tension while surfactants also reduce surface tension. Rinse aid is also notorious for ruining the head of foam on a beer served in glasses cleaned in dishwashers with rinse aid.

Has anyone tried this? If so, what sort of dosage would be effective? If not, I will conduct my own experiments and publish the results here, but I hate duplication of effort so I'd rather ask first. 😀

Also, I'd like your thoughts on this idea. Would it be likely to work or not? Any concerns related to ingredients of rinse aid liquid?

Any response would be appreciated!

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This doesn't answer your question, but perhaps you do not need to add quite as much.  If my math is correct, you are using approximately 2.5 ml/L.  We use about 1/10th of that and do not use the dishwashing liquid

We had a significant problem with foaming and tried the commercial products which worked well but were quite expensive.  We tried most of the experiments mentioned in the DIY defoamers thread.  We settled on olive oil only.  We use 300 ml for a 1350 liter ferment.  No more foam issue during ferment or puking during distillation.  Our wort is a 100% barley malt mash.  We do lauter, sparge and vorlauf.  

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I remember reading once about using olive oil as a substitute for oxygenation as well. The theory being that it contains sterols and Unsaturated Fatty Acids used to form cell walls that are normally formed by the yeast during thier initial aerobic phase. We tried it once at a brewery when we couldn't get a replacement O2 tank in time. I remember it working moderately well. Since many distillers dont aerate their wort/mash, that might be another justification for olive oil.

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Hi, everyone, and thanks for the very interesting responses so far! By and large, olive oil appears to deserve at least another look.

16 hours ago, Thatch said:

This doesn't answer your question, but perhaps you do not need to add quite as much.  If my math is correct, you are using approximately 2.5 ml/L.  We use about 1/10th of that and do not use the dishwashing liquid

We had a significant problem with foaming and tried the commercial products which worked well but were quite expensive.  We tried most of the experiments mentioned in the DIY defoamers thread.  We settled on olive oil only.  We use 300 ml for a 1350 liter ferment.  No more foam issue during ferment or puking during distillation.  Our wort is a 100% barley malt mash.  We do lauter, sparge and vorlauf.  

I believe the dishwashing liquid is supposed to act as an emulsifier. How important that is remains to be seen, of course (especially given your experiences above) but the original thread on DIY defoamers suggests a small quantity might enhance its efficacy even more. That said, if I've got my multiplications and divisions right, a 5 gallon home distiller's ferment would require only about a tablespoon, using more or less the dosage you find effective. Given that the commercial silicone-based defoamer I have here specifies a slightly higher dosage (about 7.5ml. on a 5 gallon batch of wash) that should work out well. Time to experiment and report back here!

8 hours ago, Silk City Distillers said:

Some brewing studies indicating that olive oil is beneficial for fermentation, would be doing double duty.

That is my understanding as well. Olive oil can provide lipids and other precursors to biomass, and in the right amounts facilitates cell growth and therefore promotes fermentation. Mineral-wise it would have to part of a more extensive formulation, but especially in high stress fermentations (i.e. a high OG) there is quite some evidence indicating that olive oil is a great "energy bar" for the yeast to snack on during work. 🙂

7 hours ago, adamOVD said:

I remember reading once about using olive oil as a substitute for oxygenation as well. The theory being that it contains sterols and Unsaturated Fatty Acids used to form cell walls that are normally formed by the yeast during thier initial aerobic phase. We tried it once at a brewery when we couldn't get a replacement O2 tank in time. I remember it working moderately well. Since many distillers dont aerate their wort/mash, that might be another justification for olive oil.

As far as I remember (it's been a while since I looked into that particular application) the paper I read suggested that that might be the case, but it was not exactly clear if the olive oil replace the oxygen to a certain extent, or simply made up for its lack by providing additional biomass precursors. Since the effect of both would yield similar results as far as a regular fermentation is concerned, it's difficult to tell what's what; I imagine that would require a comparative microbiological analysis of the yeast cells produced. But I digress.

Still curious about the rinsing aid liquid, though... 😀

Tnx everyone!

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