Swedish snus runs around 50% water by weight; a tobacco-free nicotine pouch can run under 4%. That single difference drives flavour release, shelf life, why snus lives in a fridge, and what a “mg/g” figure on a can actually means. No regulator anywhere sets a moisture limit — and yet Swedish law cannot be enforced without measuring it.
Moisture is the variable nobody puts on the front of the can and almost everybody gets wrong. It is why Swedish Match tells you to refrigerate the tin, why white portions are made the way they are, and why two published nicotine figures for the same product can differ by a factor of two. It is measured everywhere, reported to governments, used as the denominator for legal contaminant limits — and capped by no one. What follows is what I could establish from primary sources; where a widely repeated claim did not survive them, I say so.
“Moisture” on a snus can is not water
Start here, because everything downstream inherits the problem. When the industry says moisture it does not mean water — it means whatever evaporates when you heat the sample.
Swedish Match says so itself, in its own patent filings. European patent application EP 3 192 380 A1, “Oral Pouched Product” (applicants Swedish Match North Europe AB and Pely-tex GmbH & Co KG, published 19 July 2017) defines the term outright: moisture content refers to “the total amount of oven volatile ingredients, such as water and other oven volatiles (e.g. propylene glycol)”. The identical definition appears in a second Swedish Match patent, EP 3 330 191 A1.
Propylene glycol is a humectant — it is added deliberately to stop the product drying out. Swedish Match’s consumer FAQ confirms it uses “Food-approved moisture-preserving substances such as glycerol and propylene glycol”. CDC scientists have measured how much is there: snus products carried propylene glycol at “2.5–3.5% in mean” and glycerol at “0.04–2.1% in mean” (Wang et al., Beiträge zur Tabakforschung International 28 (2019) 203–213).
So a few percentage points of any “50% moisture” figure are not water. How many, nobody publishes — the papers that report moisture do not say whether humectants are counted in or netted out. My reading is that a published snus moisture number is an upper bound on water content rather than a measurement of it, and I would treat it that way. That is my inference from the patent’s definition and CDC’s measurements, not a claim either source makes.
The standards bodies know this. CORESTA, the tobacco industry’s analytical cooperation body, ran an interlaboratory study in 2017–18 titled, in full, “2018 Moisture (Oven Volatiles), Water by Karl Fischer and Gas Chromatography Interlaboratory Study” — set up “to make a formal comparison of water and moisture results for a variety of tobacco products”. The title does the work: moisture and water are two different measurements, and the industry thought the comparison worth a formal study. The published summary does not say which way the discrepancy runs, so I will not pretend it does.
Separately, ISO 6488:2021 exists specifically for water: “Tobacco and tobacco products — Determination of water content — Karl Fischer method”, applicable “from a mass fraction of at least 2 % to 55 %”. If oven volatiles were water, that standard would be redundant.
One more wrinkle, and it is the kind of thing that makes cross-study comparison unsafe. The drying temperature is not agreed. CDC dried at “99°C for 3 h”. CORESTA Recommended Method N° 76, the reference the FDA-funded tobacco reference products use, runs at 99 °C ± 1 °C. Swedish Match’s patent specifies, in a parenthesis that tells you the company knows it is departing from convention, that “The sample is heated to 105°C (instead of 99.5±0.5°C as in the mentioned literature references).” Different endpoints, different numbers.
How much water is actually in there
Here is the picture, each figure attached to the document it came from rather than to a round number someone repeated.
| Product type | Moisture | Source |
|---|---|---|
| Swedish snus (category average) | ~52% | Wang et al. 2019 (CDC authors), as the authors’ own characterisation |
| Traditional Swedish snus | 45–60% | ENVIRON 2010 review, commissioned by Swedish Match |
| Moist oral smokeless, generally | 50–60% | FDA MRTP review of General Snus, 7 November 2024 |
| Semi-moist oral smokeless | 30–45% | Same FDA review |
| Pouched smokeless tobacco | 30–57% | FDA PMTA Technical Project Lead review for ZYN, 2025 |
| US-made snus (three brands) | 20.5–29.5% | Lawler et al. 2013, CDC-funded measurement |
| Dry snuff | under 10% | Swedish Match patent EP 3 192 380 A1 |
| Nicotine pouches (seven brands) | 3.52–37.18% | Platt et al. 2026, Altria-funded measurement |
Two things jump out. “Snus” and “US snus” are not the same product by water content — Camel Snus measured 20.5–29.5% against a Swedish category average roughly twice that. And a tobacco-free nicotine pouch is not a drier version of snus; at ZYN’s measured 3.52% it is an order of magnitude drier, in a different physical regime altogether. Dry and moist pouches differ from each other by a lot, and from snus by more.
On provenance: the ~52% Swedish figure is the weakest of these and I want to be straight about it. Wang et al. give it in a parenthetical list of category averages with no citation attached, no stated method, and — I checked both the CDC-hosted PDF and the publisher’s page — no funding statement and no competing-interests statement at all. Treat it as CDC scientists describing their own sample set, not as a measured dataset. The Lawler figures are the stronger ones: “All research was supported by internal funds of the Centers for Disease Control and Prevention (CDC)” and “The authors report no conflicts of interest.”
White portion versus original portion is a skipped water spray
This is the single most useful thing in the patent literature, and it reframes a distinction most people describe wrongly. EP 3 192 380 A1 sets it out plainly. Pouched products “may be post-moisturized after pouch formation or not post-moisturized after pouch formation which herein is referred to as non-post-moisturized”. Post-moisturising means “spraying water on the pouched smokeless tobacco product before packaging the pouched products in cans”. And then the naming: post-moisturised products “are sometimes referred to as ‘original snus'”, while non-post-moisturised products “are sometimes referred to as ‘white snus'”.
So white portion is not a bleached pouch, not a different fleece, not a different tobacco. It is snus whose pouch did not get sprayed with water after it was filled. That is the whole mechanism, in the manufacturer’s own words.
What the patent does not establish is that white portions are measurably drier in practice, and I would not write that they are. The document gives a cascade of overlapping claim ranges — post-moisturised 45–55%, non-post-moisturised 30–60% — which overlap right where most products sit. Patents draft claim scope; they do not report measurements. The supporting evidence runs the same way: FDA’s 2015 substantial-equivalence review of General portion products describes a white-versus-original moisture decrease as “small” (the figure itself is redacted), and lists the same 1000 mg portion mass for General Portion Original Large and General Portion White Large. The process difference is solid. The magnitude is not published by anyone.
The patent is also candid that the point of white was looks, not performance: non-post-moisturised products “are by some users considered to have a more appealing appearance”. No claim about drip, no claim about release.
Nobody regulates moisture — and Swedish law cannot work without it
I went looking for a moisture ceiling or floor everywhere one could plausibly live. There isn’t one. Sweden is the obvious place to check, because Sweden is the only EU country with a legal snus market and it regulates snus as a food-adjacent product. The governing regulation is LIVSFS 2024:2 (decided 16 February 2024, in force 1 April 2024), and it runs to twenty sections covering ingredients, additives, flavourings, novel foods, water, contaminants, hygiene, HACCP, food-contact materials, labelling, traceability and registration. The words fukt (moisture), fukthalt, vattenaktivitet (water activity) and torrsubstance appear in none of them.
The one water provision, § 7, is about water quality going in, not water staying in. In the official text Sweden notified to the European Commission: “The water used in the production and preparation of snus, snus-like products and chewing tobacco shall comply with the requirements laid down in the Swedish National Food Agency’s Regulations (LIVSFS 2022:12) on drinking water.” The water you add to snus must be drinking water. How much of it ends up in the can is not the law’s business.
Except that it is, twice over, in the very next section. LIVSFS 2024:2 § 8 sets four contaminant limits, and it mixes bases inside a single paragraph: lead at 3 mg/kg and aflatoxins at 0.005 mg/kg with no basis stated, but benzo(a)pyrene at “0.003 mg/kg dry weight” and tobacco-specific nitrosamines NNN+NNK at “2 mg/kg dry weight”. A dry-weight limit cannot be applied without determining how much water is in the sample. So Sweden sets no moisture standard and simultaneously makes moisture indispensable as a denominator for half its contaminant limits.
And it names no method for doing it: “Dry weight shall be determined by an established method which has been shown to determine this content accurately.” No standard, no temperature, no reference to CORESTA or ISO. Set that against § 7, which pins water quality to a specific named regulation by number. The regulator was precise about the water going in and silent about the water staying in.
The industry’s own standard is no different. GOTHIATEK — the voluntary limit list that Swedish Match holds its own snus to — carries sixteen parameters: nitrite, NNN+NNK, NDMA, B(a)P, aflatoxins, ochratoxin A, formaldehyde, crotonaldehyde, cadmium, lead, arsenic, nickel, chromium, mercury, acetaldehyde and agrochemicals. Moisture is not among them, and the words “moisture”, “water”, “water activity” and “dry weight” do not appear on the page.
What GOTHIATEK does say is the basis, and this is worth pausing on: “In the table below, the limits and the average contents are based on snus, ‘as is'”, with the units glossed as “mg/kg = thousandth gram per kilogram product (based on moist snus)”. So GOTHIATEK’s NNN+NNK limit of 0.95 mg/kg is on a moist basis while Swedish law’s limit of 2 mg/kg is on a dry basis. Those two numbers are not comparable as printed. At roughly 50% moisture the voluntary standard converts to something near 1.9 mg/kg dry — which is to say the industry limit and the legal limit are far closer than the face figures suggest. (The 0.95 and the 2, and both basis labels, are quoted; the doubling is my arithmetic, using the same 50%-moisture assumption the industry’s own commissioned review uses.)
The United States takes the third possible approach: collect it, never limit it. The CDC’s “Recommended Format for Smokeless Tobacco Nicotine Data Reporting”, issued under the Comprehensive Smokeless Tobacco Health Education Act (15 U.S.C. § 4403(a)), has a column for “Total moisture (%)” alongside nicotine and pH. Manufacturers must report moisture to the federal government. No federal rule says what it may be.
The 2× problem hiding inside every mg/g figure
If nicotine is expressed per gram of product and roughly half the product is water, then whether the gram is wet or dry changes the number by a factor of two. For pouches, where mg per pouch and mg per gram already get confused, that is a second ambiguity stacked on the first.
The sharpest evidence that this is a real problem and not a theoretical one comes from the review Swedish Match itself commissioned. ENVIRON International Corporation’s 2010 “Review of the Scientific Literature on Snus”, prepared for Swedish Match, states its working assumption openly in a footnote — “In this report, 50% moisture is assumed for traditional Swedish snus” — and its conversion rule in a table footnote: “Assuming 50% moisture, values for wet weight were converted to dry weight by multiplying by 2.”
It had to assume, because the papers did not say. The same review flags the omission three separate times: “It was not specified if these values are based on wet or dry weight” (nitrosamines); “These authors did not specify if the values were given as per wet or dry weight” — that one is about nicotine; “The latter authors did not specify if the values were based on dry or wet weight”. A review paid for by the manufacturer, about its own product, cannot tell you which basis the published nicotine figures are on.
CDC, to its credit, labels its columns: Lawler et al. print “Total nicotine (mg/g, wet)” and “Unprotonated Nicotine (mg/g, wet)” in the table headers, and spell out why moisture is measured at all — “Moisture content measurements provide a means of calculating products values on a wet weight or a dry weight basis.”
And here is the part that genuinely surprised me. Swedish law does not require a nicotine figure on a snus can at all. LIVSFS 2024:2 § 12 lists exactly four things a consumer pack must carry: net quantity in grams, date of manufacture, a storage instruction where storage affects shelf life, and the name and address of the manufacturer, packer or seller. Nicotine content is not on the list. So every mg/g on a Swedish snus can is voluntary, with no prescribed basis, no prescribed method and no legal definition — while the same regulation demands dry-weight precision for nitrosamines. The law is more exacting about nitrosamines per dry kilo than about the nicotine dose it declines to regulate at all.
I would not put much faith in an unlabelled mg/g figure. If the basis is not stated, it could be out by two.
What moisture does to pH, and therefore to the hit
There is a chain from water content to the number people quote as “free nicotine”, and it runs through the measurement method rather than through the mouth.
pH is not a property of snus. It is a property of a water suspension of snus. CDC’s protocol: “Duplicate pH measurements were performed by suspending 2.0 g of tobacco product in 20 mL deionized distilled water”. Free-base nicotine is then not measured at all but calculated — the percentage in the unprotonated form “was calculated using tobacco product pH and the pKa value of the pyrollic nitrogen of nicotine (8.02), which is substituted into the Henderson-Hasselbalch equation”. Why it matters: “Nicotine absorption across oral mucosa is highly dependent upon product pH, which influences the proportion of total nicotine present in the unprotonated form.”
So moisture sits upstream of the free-base figure by way of the method. And the product’s own dryness forced CDC to change that method: “A 2.0g sample of a very low moisture product prepared in 10 mL water produced a thick paste-like consistency that could not be adequately stirred and measured. Doubling the water volume (20 mL) produced a slurry more amenable to analysis.”
Before anyone builds a theory on that, CDC quantified the effect and it is small: “The pH differences between the 10 mL or 20 mL preparations in this study were on the order of ±1.0%”, with the worst case “the dry snuff (no pouch) products with a maximum 3.1% difference”, and products above pH 7.0 showing “little or no change”. It is a real methodological dependency, honestly reported, and it is not the dominant term in why one product hits harder than another.
Why snus lives in a fridge — and it is not bacteria
Ask most people why snus is refrigerated and you get an answer about microbes. The manufacturer’s own stated reason is different. ENVIRON, citing Swedish Match directly: the final product “is stored at or below 8°C prior to packaging” — “to slow the normal ageing process and to preserve moisture”. And elsewhere in the same review: “cool storage of snus was introduced to prevent loss of moisture and aging of the final product”. The bacterial explanation appears in that document too, but ENVIRON attributes it to “some authors”, not to the company.
Swedish Match’s consumer FAQ reads the same way. “Since our Swedish snus is classed as food, it must be stored in a cold place.” “Most often old snus just dries out and loses much of its aroma and flavor.” “We always label the snus cans with a ‘Best before’ date.” And the shelf lives track moisture class exactly: “the shelf life for moist loose snus is 14 weeks, for moist portion-packed snus 20 weeks and for the dry assortments 30 weeks”. Drier lasts longer, because there is less to lose.
The format matters too, in the company’s own words: “Since portion-packed snus is more sensitive to drying out than loose snus, it requires a tighter can.” A pouch has more surface area per gram than a pinch, so it dries faster, so the can has to seal better. That is also why Swedish law requires a storage instruction only “where storage affects shelf life” — moisture-driven shelf life is real enough to be legislated for indirectly while being unregulated directly.
One tempting story does not survive checking. Warm storage does not drive nitrosamine formation in snus. ENVIRON, relaying Brunnemann et al. 2001: “storing temperature has influence only on TSNA formation in fermented STPs, but not in snus.” Pasteurised, unfermented Swedish snus behaves differently from fermented American moist snuff. Heat ruins snus by drying it out and flattening the flavour, not by generating nitrosamines.
Storage does cost you potency, though, and the figure is dramatic: six months at room temperature took one sample of traditional Swedish snus “from approximately 56% to less than 30%” moisture. ENVIRON’s summary of the literature is that “aged and inappropriately stored snus may deliver less nicotine than snus freshly manufactured”. The same logic applies, with different numbers, to how long a can of pouches stays good.
FAQ
How wet is Swedish snus?
Published figures cluster around 45–60%, with roughly 50% the usual working assumption — including in the literature review Swedish Match itself commissioned. No regulator or manufacturer publishes a per-product moisture figure, so treat any specific number for a specific brand with suspicion unless it names its source and method.
Are white portions drier than original portions?
They are made by skipping the post-moisturising water spray, which is a real and manufacturer-documented process difference. Whether the finished product measures drier is not established by any published number: the patent’s ranges overlap, FDA called the difference “small” without printing it, and the portion masses FDA lists are identical. I would say white portions are made drier, not that they are measurably drier.
Is there a legal moisture limit for snus?
No — not in Sweden, not in the EU, not in the US, and not in GOTHIATEK. Sweden regulates the quality of the water that goes in, and uses dry weight as the basis for two of its four contaminant limits, but sets no ceiling or floor on water content.
Does moisture change how strong a pouch feels?
Indirectly and not simply. Moisture affects how pH is measured and therefore the calculated free-base figure, but CDC puts that methodological effect at about ±1%. What moisture more plausibly changes is release rate and flavour, and no primary source I could find quantifies that for snus.
Why is a nicotine pouch so much drier than snus?
Different design goals. Snus is refrigerated to preserve moisture; FDA’s review of ZYN accepted that “The lower moisture content of the new products is less conducive to microbial growth compared to pouched smokeless tobacco products or General Snus”. Same variable, opposite engineering intent. What is actually in a pouch follows from that choice.
Should I refrigerate my pouches too?
Makers of tobacco-free pouches say no. ZYN’s own FAQ: “Nope, refrigeration isn’t necessary”, with the product to be kept “at normal room temperature and humidity”. That is consistent with a product carrying a few per cent water rather than fifty.
Sources
- Swedish National Food Agency, LIVSFS 2024:2, Livsmedelsverkets föreskrifter om snus, snusliknande produkter och tuggtobak — decided 16 February 2024, in force 1 April 2024. §§ 7, 8, 12, 15.
- European Commission, TRIS notification 23913 — the English text of LIVSFS 2024:2 as notified by Sweden.
- Livsmedelslag (2006:804), Swedish Parliament document service. § 6 p. 3 (delegation of power over “livsmedels beskaffenhet”).
- Swedish Match North Europe AB and Pely-tex GmbH & Co KG, EP 3 192 380 A1, “Oral Pouched Product”, published 19 July 2017 (European Patent Office publication server).
- Swedish Match, The GOTHIATEK standard and consumer FAQ. Company sources, read as such.
- ENVIRON International Corporation, Review of the Scientific Literature on Snus, 31 March 2010 — prepared for Swedish Match. Industry-commissioned; cited here for its own methodological admissions.
- Lawler TS, Stanfill SB, Zhang L, Ashley DL, Watson CH, “Chemical characterization of domestic oral tobacco products”, Food and Chemical Toxicology 57 (2013) 380–386, doi 10.1016/j.fct.2013.03.011, via CDC Stacks. Funding: internal CDC funds; no conflicts declared.
- Wang L, Stanfill S, Valentin-Blasini L, Watson CH, Bravo Cardenas R, “LC-MS/MS Analysis of Sugars, Alditols, and Humectants in Smokeless Tobacco Products”, Beiträge zur Tabakforschung International 28 (2019) 203–213, via CDC Stacks. No funding or competing-interests statement is published with this paper on either the CDC copy or the publisher’s page.
- FDA Center for Tobacco Products, PMTA Technical Project Lead review, STNs PM0000593–PM0000612 (ZYN), signed January 2025. Section 3.2.1.3.
- FDA Center for Tobacco Products, Technical Project Lead Review of Modified Risk Tobacco Products, General Snus, 7 November 2024.
- FDA Center for Tobacco Products, Technical Project Lead Review, SE0010524–SE0010533, 2 November 2015 — portion masses for General products.
- CDC Office on Smoking and Health, Recommended Format for Smokeless Tobacco Nicotine Data Reporting, under 15 U.S.C. § 4403(a).
- CORESTA, 2018 Moisture (Oven Volatiles), Water by Karl Fischer and Gas Chromatography Interlaboratory Study.
- ISO 6488:2021, Tobacco and tobacco products — Determination of water content — Karl Fischer method.
Last verified: 9 October 2026.