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I consider making a Nutella-like spread on my own, seeing how it would be much cheaper and also could be made to contain more hazelnuts and less (non-palm) vegetable oil or sugar.

Looking at Nutella's ingredients, it contains no preservative: sugar, vegetable oil (probably palm), hazelnut (13%), skimmed milk powder (8.7%), low fat cocoa powder (7.4%), soy lecithin, flavoring (probably synthetic vanillin). 30.9% fat, 56.3% sugars.

After opening it doesn't seem to mold or anything even after several months outside of the fridge.

Yet someone asked a similar question here about their hazelnut spread going bad within weeks. The answers weren't that clear.

The person said they added a small amount of hot water to the mixture, and it isn't mentioned the mixture was heated at any point. Some people commented that might've been the culprit, but beyond mold the risk for botulism was also mentioned.

So my question is whether using an almost-exact replication of the Nutella ingredients, no water and heating it up to a certain (?) degree (plus storing in a sterilized container) could promise long-term consumption safety? Is there a minimum % of sugar recommended? And is botulism an actual risk with such a product?

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  • Note that you don't need any additional oil beyond the hazelnuts to get a Nutella-like consistency. Pure hazelnut butter has a spread like consistency (and is a tasty breakfast spread). Adding in cacao powder will make a chocolaty nut butter. Add in caster sugar to get some sweetness. All the other ingredients are not needed.
    – quarague
    Commented Sep 19, 2022 at 11:44
  • @quarague That's possible, although I assume you would need a very good food processor to produce a completely smooth butter from that, and it might have a less-spreadable consistency. Also, it would probably have a slightly higher final water content, but it was quoted as far enough on its own from bacteria-hospitability levels.
    – TLSO
    Commented Sep 19, 2022 at 15:01
  • From experience, a cheap food processor will suffice but you have to be patient and not do all the grinding in one go so it doesn't overheat. I don't know where you get the higher water content, hazelnuts contain very little water (about 3% if I read the table in the answer correctly) and I suggested adding 2 dry powders.
    – quarague
    Commented Sep 19, 2022 at 16:16
  • @quarague I assume vegetable oil contains practically no water, so it probably contributes less water than an additional mass of hazelnuts. Is there a recommendation to what level should you roast the hazelnuts before the grinding?
    – TLSO
    Commented Sep 19, 2022 at 20:09

1 Answer 1

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In short: your recipe for a heated hazelnut spread is safe.

The previous question and answers did not address the effect of water activity (Aw) on microorganism growth and safety. The added water in conjunction with the sugar and added protein were the root cause of mould growth in that scenario.

In most foods, the water present may be bound to components within the food like salts and sugars, making less of it available for use by microorganisms. The amount of available water, Aw, is a measurement of how much water is not bound - typically, a value below 0.92 inhibits Clostridium botulinum growth, and below 0.85 most organisms including yeasts and moulds will not grow at all, making the food shelf-stable. This is just for stopping growth, and does not account for other effects in the food - i.e. stress or lethality from osmotic or acid stress.

The presence of Salmonella on raw hazelnuts is documented and cited by the US FDA, though at a lower prevalence than for other tree nuts [1] - roasted and other processed forms are not included.
Nutella relies on the effects of water activity to prevent pathogen/spoilage growth and survival after a lethality cook process from roasting. The added dry ingredients and hazelnuts themselves start at a water activity less than 0.85 - some articles cite a range below this for quality purposes to inhibit lipid oxidation [2,3], and the Oregon Hazelnut Industry claims a range of 0.46-0.49 for dry roasted products. Under the ideal drying and storage conditions for hazelnuts, Salmonella viability decreases as well [4].

Salmonella in tree nuts

Findings of Salmonella in raw tree nuts. From:
"Prevalence of Salmonella in Cashews, Hazelnuts, Macadamia Nuts, Pecans, Pine Nuts, and Walnuts in the United States". [1]

Water activity of hazelnut varieties

Physical characteristics of hazelnuts. From:
"The hygroscopic behaviour of the hazelnut". [3]

[1] Prevalence of Salmonella in Cashews, Hazelnuts, Macadamia Nuts, Pecans, Pine Nuts, and Walnuts in the United States.
Guodong Zhang, Lijun Hu, David Melka, Hua Wang, Anna Laasri, Eric W Brown, Errol Strain, Marc Allard, Vincent K Bunning, Steven M Musser, Rhoma Johnson, Sofia Santillana Farakos, Virginia N Scott, Régis Pouillot, Jane M Van Doren, Thomas S Hammack.
https://doi.org/10.4315/0362-028x.jfp-16-396

[2] Effect of drying methods on long term storage of hazelnut.
Ali TURAN, KARAOSMANOĞLU.
https://doi.org/10.1590/fst.20518

[3] The hygroscopic behaviour of the hazelnut.
A.Lopez, M.T.Pique, M.Clop, J.Tasias, A.Romero, J.Boatella, J.Garcia. https://doi.org/10.1016/0260-8774(94)00021-Z

[4] Salmonella Survival Kinetics on Pecans, Hazelnuts, and Pine Nuts at Various Water Activities and Temperatures.
Sofia M Santillana Farakos, Régis Pouillot, Susanne E Keller.
https://doi.org/10.4315/0362-028x.jfp-16-392

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  • Thank you, a comprehensive answer. I still want to make sure whether heating the mixture to some specific degree is required or not, even if the ingredients should have the preservative effects of a low Aw product.
    – TLSO
    Commented Sep 18, 2022 at 11:45
  • That's fine as well - the minimum temperature for Salmonella lethality is more than achieved when roasting the hazelnuts, though you can heat the entire mixture alone to the general recommended 72C/165F for added peace of mind. Be sure to allow the mix to fully cool before filling otherwise any moisture released as steam may condense on the surface, creating a localized high water activity zone.
    – borkymcfood
    Commented Sep 18, 2022 at 12:05
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    The concern isn't the survival of spores, but a hospitable anaerobic environment for them to germinate and release their toxins. C. botulinum is inhibited from germination at Aw 0.92 stated above, meaning there's negligible risk of germination in your preparation as long as there's no added water. The spores also survive in anaerobic/hermetically sealed, pasteurised-not-sterilised foods like canned acidified fruits and tomatoes, and honey - like Nutella, they're inhospitable to germination of spores.
    – borkymcfood
    Commented Sep 18, 2022 at 14:56
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    For further reference, "Influence of water activity and storage conditions on survival and growth of proteolytic Clostridium botulinum in peanut spread" - doi.org/10.1006/fmic.1999.0292
    – borkymcfood
    Commented Sep 18, 2022 at 15:02
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    The 250F/121C 3 minute heating is pressurized thermal lethality for high moisture, high water activity foods at risk or not innately inhibitory to C. botulinum germination. The nut butter you wish to make is very low moisture and low water activity and innately inhibitory. It is not a requirement for this type of recipe. This heating will affect texture aspects - for sugar alone, refer to: foodcrumbles.com/sugar-cooking-temperature-stages/…
    – borkymcfood
    Commented Sep 19, 2022 at 6:02

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