What Is the Difference Between Augeo-Type Diffuser Bases, DPG and Alcohol-Based Formulas for Reed Diffusers?

The short answer: three solvent routes, one ready-made route

When makers talk about "diffuser bases" they usually mean one of four things. DPG (dipropylene glycol) is commonly described as a low-odour, relatively slow-evaporating glycol carrier, and is probably the most familiar single diffuser solvent. Augeo-type bases usually means Augeo Clean Multi, a trade-named solketal-type solvent that its maker and distributors commonly market for air care and diffusers, or blends built on it. Alcohol-based formulas use perfumer's alcohol or another ethanol-based carrier; they evaporate fast and are highly flammable, which changes packaging, shipping and storage. And ready-made bases are finished carriers a supplier has designed for reeds and sells as one product — CSI's five are in this group, and their composition is not published.

That last point shapes the whole page. Because CSI does not publish what its bases are made of, we will not tell you that any of them is "DPG-based", "Augeo-type" or "alcohol-free". A ready-made base is its own route: you judge it by behaviour, not by ingredient list. Everything this page says about DPG, Augeo-type solvents and alcohol comes from general industry knowledge and is phrased that way — commonly described, commonly marketed — with no viscosity, evaporation or flash-point figures, because those vary by grade and supplier and would not tell you how your oil behaves on your reeds anyway. CSI sells none of the three solvents.

So the practical answer to "what is the difference?" has two halves. The first half is what the routes are commonly said to do, and the safety and logistics consequences that follow; that narrows your shortlist before you spend anything. The second half is how they actually behave with your oil, and that only a side-by-side test answers. This pillar does both: a comparison of the four routes, a five-question shortlist, and a priced four-route test with Jasmine at 20% in the 120 ml Gold Reed Diffuser Bottle 120 ml.

If you have already decided on the ready-made route and want to know which of CSI's five bases to buy, the base-selection pillar shortlists them by fragrance family; this page stays with the question of solvent routes.

DPG: the slow, low-odour glycol

DPG is the route most people have heard of first. It is commonly described as a clear, low-odour glycol that mixes with many fragrance oils and evaporates relatively slowly. Those three descriptions explain both its popularity and its main complaint. Low odour means the carrier rarely competes with the fragrance. Slow evaporation is commonly associated with a longer-lasting bottle. And slow evaporation is also why some makers find DPG diffusers quiet, particularly in large or air-conditioned rooms.

DPG is also commonly described as thicker than many lighter perfumery solvents, which raises the question of whether it travels up reeds fast enough. That is a measurable question, not a matter of opinion: DPG alone and viscosity gives a reed-bundle uptake test and a reed-count arm that often shows the reed surface, not the carrier, is the limit. DPG is sold in different grades by different suppliers; if you use it, specify one grade, ask for its safety data sheet and keep the source constant. Ready-made base versus DPG for commercial diffusers covers the consistency and documentation work this hands to you.

Augeo-type solvents: the marketed diffuser solvent

"Augeo-type" almost always refers to Augeo Clean Multi, a trade-named solvent of the solketal type, which its maker and distributors commonly market for air-care products including reed diffusers. Some ready-made bases on the wider market are described by their makers as Augeo-based, and some makers blend it with other solvents. Because it is a branded material, the most reliable descriptions of it come from its maker's own technical documents — read those for its odour, evaporation, safety and handling data rather than relying on a forum summary, and ask your distributor for the current safety data sheet.

What you can say in general is that it is positioned as a purpose-chosen diffuser solvent rather than a general glycol, that makers commonly choose it when they want an alternative to DPG, and that like every solvent it does not mix equally well with every fragrance oil at every load. None of that tells you whether it will be stronger or longer-lasting than DPG or a ready-made base with your jasmine in your bottle. Treat any marketing line about "better diffusion" exactly as this series treats CSI's own base-page lines: a hypothesis for your scale and your nose.

Alcohol-based formulas: fast, bright and flammable

Perfumer's alcohol and other ethanol-based carriers are the fine-fragrance route applied to reeds. They evaporate fast, they lift top notes into the room quickly, and they carry an alcohol note on opening that fades as it leaves. In a reed diffuser, fast evaporation is commonly associated with a strong first impression and a shorter life, and with a scent that may change over the bottle's life as the alcohol leaves ahead of heavier fragrance materials. Some commercial formulas use a share of alcohol inside a blend for that first-impression lift; some avoid it entirely.

The bigger differences are practical, not olfactory. Alcohol-based liquids are highly flammable. That means storing stock and finished bottles away from heat, sparks and open flame — including candles, which matters if you make both in one workspace — and following the supplier's SDS for storage quantities and ventilation. It also commonly means restrictions or extra paperwork when shipping flammable liquids by courier, which affects whether you can sell nationally from a website, and labelling obligations on the finished product. Many makers choose "alcohol-free" precisely to avoid those questions; making a 100 ml diffuser without alcohol is the series pillar for that route, and perfumer's alcohol as a reed diffuser base covers the flammability, packaging and performance questions in depth.

Two things not to do. Do not add alcohol to a ready-made base to "speed it up" — you change a designed product into an untested one and add a flammability question its maker did not design for. And never use cleaning alcohol: CSI's Isopropyl Alcohol Spray (₹383.00 for 150 ml, ₹520.00 for a litre) is sold for cleaning jars and tools, not as a diffuser solvent.

Ready-made bases: judged by behaviour, not label

A ready-made base exists so that you do not have to design a carrier. You add your fragrance oil to a finished product, at the supplier's recommended range, and the supplier carries the job of making the carrier consistent from batch to batch. CSI lists five in stock — Pure Performance Base, Longevity Base, Lift Base, Depth Base and Softness Base — each with a page that says which fragrance families it is for, all with a 10–30% range and a 24–48 hour rest. A sixth, the CSI HyperDiffusion Base™, is out of stock.

What a ready-made base does not give you is a solvent label. You cannot put CSI's bases into the DPG / Augeo / alcohol taxonomy, because what they are made of is not published. For most commercial makers that matters less than it sounds: what you sell is a bottle that stays clear, smells right in a room and lasts long enough, and those are behavioural properties you measure. Where it does matter — a compliance file, a retailer's questionnaire — ask CSI on WhatsApp whether a safety data sheet or technical data sheet is available for the specific base, and see what to check on an SDS and TDS for what to look for.

Five questions that shortlist your route before you test

Before spending on solvents, answer five questions honestly. Each one removes a route or adds a test. The diagram at the top of this page draws them as a tree; here they are with the reasoning.

Most commercial makers who ship nationally end up with two or three routes on the shortlist, not four. A maker selling only at local markets, with bottles that never travel by courier, might keep all four. Whatever survives goes into the side-by-side below, with the ready-made base for your family as the reference arm.

The side-by-side: up to four routes, sixteen bottles

One oil, one load, one bottle, one reed type; only the carrier changes. The worked example uses Jasmine at 20% by weight in the 120 ml Gold Reed Diffuser Bottle 120 ml, with an example fill of 110 ml — 110 g at an example 1.00 g per ml, a fill you choose because the bottle page publishes no fill line. That is 22.0 g of oil and 88.0 g of carrier per bottle, and 7 white fibre reeds in every reeded bottle. Drop any route your shortlist removed.

The carriers will not all weigh the same per millilitre. An alcohol-based blend may be noticeably lighter than a glycol at the same fill line, for example. That is why every bottle is filled by weight at a fixed load, and why the comparison uses projected days (fill grams ÷ grams per day), not grams per day alone: a bottle holding fewer grams that loses fewer grams per day can last exactly as long as a heavier one.

Scoring the routes: strength, life and the change over time

Score on a house scale you write down before day 0 — for example 0 (nothing) to 5 (fills the room) at the door after 30 minutes, door closed, fan and AC off — and never change it between rounds. There is no industry scale for diffuser strength, so yours is the standard. Then add the dimension that separates these routes most: how the score moves between day 3 and day 21. A route that starts at 4 and falls to 2 is a different product from one that holds 3 throughout, even if their day-14 scores are equal.

A working rule for picking a route: it must pass clarity at every checkpoint in all three bottles and its hold-back; its projected life must meet the target you wrote down; and its average blind score at day 14 and day 21 must be within one point of the best route that also passes. Among the routes that clear all three bars, choose on logistics and cost. If no route except the alcohol one meets your strength target, that is information too: it usually means the room, reed count or load needs attention before the carrier, which a 20% diffuser that cannot fill a bedroom and how many reeds to test cover.

Cost: price every route per bottle

Carrier prices are quoted per kilogram or per litre and almost always look very different between routes. Per bottle, the carrier matters more than many makers expect: at 20% load it is four-fifths of the liquid by weight, and with a listed ready-made base it is the single largest line. At production rates — jasmine at its 1 kg rate of ₹3.92 per gram, Lift at ₹1,099.00 per 500 ml converted at the example 1.00 g per ml — one 120 ml bottle at 20% costs:

Now the useful number for comparing routes: the carrier price at which another route costs the same per bottle as Lift. At the example density that is ₹2,198.00 per kilogram of carrier (between ₹2,093.33 and ₹2,313.68 across the ±5% density range). Any solvent you can buy, delivered, for less than that per kilogram is cheaper in carrier cost; the table below shows how much cheaper at a range of prices. These are not market prices for DPG, Augeo-type solvents or alcohol — they are values for you to compare your own quotes against.

Three costs never appear in that grid. First, the alcohol route's logistics: flammable-liquid shipping, storage and labelling are real costs in money and time, and can decide whether you can sell by courier at all. Second, testing and consistency: each self-sourced solvent needs its own lot checks and documentation. Third, failures: one clouded or weak batch wipes out the carrier saving on a great many bottles. Premium base or blend your own solvents? works through those hidden costs in full, and comparing base prices per kg shows how density and yield change a per-kilogram comparison.

The priced side-by-side kit

Listed, in-stock CSI packs only, CSI live pricing, pulled 14 October 2026 for Lift, bottles, reeds and scale and CSI live pricing, pulled 24 September 2026, stock re-checked 14 October 2026 for jasmine. Grams include a 5% working allowance. The three solvent routes are not CSI products and are not priced; you need 369.6 g of each for its arm and hold-back.

If your shortlist leaves only one solvent route against the ready-made base, the round shrinks to 8 bottles in 1 pack of 10, 1 × pack of 50 of white reeds and the same 500 ml of Lift: ₹2,611.00 in CSI materials. Jasmine is one of the oils where a bigger pack is genuinely cheaper per gram — ₹4.30 at 100 g against ₹3.92 at 500 g and ₹3.92 at 1 kg — but this round needs only 370 g, and four 100 g packs (₹1,720.00) cost less in total than one 500 g (₹1,961.00). Buy the 500 g or 1 kg when a route goes into production, not for the test.

The decision rule

Run the rule per fragrance. It is entirely sensible to end up with a ready-made base for your florals, DPG for a woody line and no alcohol anywhere because you ship nationally. Record each decision with the test it came from in the SKU's formula sheet, and repeat the test whenever you change supplier for any carrier — testing a new base supplier sets out the minimum retest.

The CSI products in this test

Where this fits in the series

This is one of the series' five pillar pages. Which reed diffuser base should I buy in India? is the pillar and hub for choosing among CSI's five ready-made bases by fragrance family. How to make a 100 ml diffuser without alcohol is the method pillar. How much fragrance oil to add owns load, by-weight maths and IFRA Category 10A, and starting a profitable reed diffuser business ties the whole series to a costed plan. Ready-to-use base or your own solvents? covers the same choice from a beginner's side, and making diffusers without water explains why no route here uses water.

Frequently asked questions