Glass Baby Bottles Buying Guide: BIBS Latex Nipple Sizes

Start With the Nipple, Then the Bottle

Most bottle shopping starts with the bottle body, but the part your baby actually works with is the nipple. The BIBS Glass Baby Bottle pairs a borosilicate glass body with a natural rubber latex nipple, and the two sizes in this lineup differ in both capacity and nipple flow. That makes the first real decision a flow decision: the 4oz bottle ships with a slow-flow latex nipple, and the 8oz bottle ships with a medium-flow latex nipple.

If you are comparing latex against silicone, the supplied BIBS record describes the latex nipple as skin-soft with a breast-like shape that mirrors the BIBS Colour pacifier. That pacifier match is the specific claim to weigh, not a general promise that every baby will accept it. Latex is also a material some families avoid, so check your own preferences before committing to a set.

4oz vs 8oz: Which Size to Buy First

Both bottles are sold as two-packs and share the same glass body, anti-colic valve and accessory set. The difference is capacity and the nipple flow included in the box.

• 4oz (110ml) two-pack: Ships with slow-flow latex nipples. The smaller capacity suits shorter feeds and early bottle introduction, and the slow flow gives you the gentlest starting point in this lineup. If you are building a baby bottle starter set, this is the more natural first purchase.
• 8oz (225ml) two-pack: Ships with medium-flow latex nipples. The larger capacity makes sense once feeds get longer, and the medium flow is the middle step in BIBS's slow, medium and fast flow range. Buying this first means starting one flow step above the slowest option.
• Buying both: A 4oz set plus an 8oz set gives you four bottles and two flow levels without buying separate nipple kits. Additional BIBS nipple kits are sold separately, so this is also a way to cover both stages in one order.

What Each BIBS Set Includes

• BIBS - Glass Baby Bottle 4oz Latex - 2 Pack Ivory: 2 x 110ml / 4oz glass bottles with slow-flow natural rubber latex nipples, plus a bottle cap, screwcap, Milk Lock and collapsible funnel. The 4oz set is a complete, ready-to-use pair with the slowest flow in the range, which is why it works as a starter set.

  

  BIBS - Glass Baby Bottle 4oz Latex - 2 Pack Ivory

• BIBS - Glass Baby Bottle 8oz Latex - 2 Pack Blush: 2 x 225ml / 8oz glass bottles with medium-flow natural rubber latex nipples, plus the same cap, screwcap, Milk Lock and collapsible funnel. You get the same accessory kit at the larger capacity, so the upgrade cost is really about size and flow rather than missing parts.

  

  BIBS - Glass Baby Bottle 8oz Latex - 2 Pack Blush

Glass vs Plastic: The Trade-Offs That Matter

The BIBS body is lab-grade borosilicate glass, which the record describes as resistant to temperature change, thermal shock, scratches, stains and odors, and microplastic-free. Those are the practical reasons families choose glass: it does not hold onto smells or stains the way some plastics can, and it is built to last rather than be replaced.

The honest trade-off is weight and breakage risk. Glass is heavier in the hand and can shatter if dropped, and the supplied information does not include a silicone sleeve or other drop protection for these bottles. If you bottle-feed away from home often, plan for how you will carry and store glass. The included Milk Lock is described as hygienic, spill-proof storage for on-the-go, which helps with transport, but it is not a drop guard.

One more point in glass's favor for daily use: the bottle body is top-rack dishwasher safe and microwave safe. That convenience is part of the value, provided you follow the care limits below.

Care Rules That Decide Whether Glass Is Right for You

These come from the supplied BIBS care and sterilization information. They are the constraints that separate a happy glass-bottle household from a frustrating one.

• Sterilize before every use: BIBS recommends sterilization before every use and never exceeding 100°C. Do not seal the bottle during sterilization.
• First-use sterilization: Sterilize all components in boiling water for 5 minutes before first use.
• Dishwasher and microwave limits: The bottle body is top-rack dishwasher safe and microwave safe. The funnel and nipple are hand-wash only.
• Nipple replacement: Inspect latex nipples regularly and replace them every 1–2 months, or sooner if damaged. Factor replacement nipples into your budget.

How Many Bottles Do You Actually Need?

The supplied records do not give a recommended number of bottles, so treat any specific count as a personal routine decision rather than a manufacturer instruction. What the records do give you is the math of a two-pack: one 4oz set is two bottles, and one 8oz set is two bottles. A starter set of four bottles (one of each set) covers a small rotation if you wash once a day, while a single two-pack means washing more often or keeping a backup on hand.

Because latex nipples need replacing every 1–2 months, the number of bottles you own also affects how many spare nipples you keep. If you run four bottles, you may want spare nipple kits sooner than a two-bottle household would. The 4oz and 8oz sets both include two nipples, so a four-bottle setup starts with four nipples in two flow levels.

Prices and Set Details at a Glance

• BIBS - Glass Baby Bottle 8oz Latex - 2 Pack Blush: BIBS Glass Baby Bottle 8oz Latex 2 Pack Blush is listed at USD 20.97, compared with a catalog comparison price of USD 29.95. The larger set with medium-flow nipples is the lower-priced of the two at the time of writing, which makes it worth checking before you assume the bigger bottle costs more.
• BIBS - Glass Baby Bottle 4oz Latex - 2 Pack Ivory: BIBS Glass Baby Bottle 4oz Latex 2 Pack Ivory is listed at USD 19.77, compared with a catalog comparison price of USD 29.95. The starter-size set is close in price to the 8oz set, so choose by flow and capacity rather than by a large price gap.

What the Supplied Information Does Not Settle

The records do not list an age or weight range for either bottle, so they cannot tell you when to move from slow to medium flow. They also do not confirm whether the bottles are compatible with other brands' nipples or whether a travel cap or sleeve is available. If those details matter to you, confirm them with the store before buying rather than assuming.

What is clear is the core choice: a 4oz slow-flow pair for a gentle start, an 8oz medium-flow pair for longer feeds, or both for a four-bottle rotation with two flow levels. Weigh that against the glass care routine and the regular latex nipple replacement, and you have enough to choose without guessing.